Semidesert Grassland

The semidesert grassland complex of climax range communities comprises the most xeric grasslands in North America. There are two larger and more general regions of semidesert grassland in North America both of which are associated with the Basin and Range physiographic province and major climatic deserts therein. A third and more restricted regional semidesert grassland is associated with the Colorado Plateau province. The larger and better known of of the two regional semidesert grasslands (grassland complex) is that affiliated with the "warm" Chihuhuan and Sonoran Deserts. The Chihuhuan-Sonoran regional unit of pre-Columbian climax range vegetation dominated by grasses occurred as both 1) a transition zone (= ecotone) between semiarid prairies and plains grasslands and natural desert scrubland and 2) a mosaic of smaller grasslands and areas of Chihuhuan and Sonoran Deserts. Pre-Columbian semidesert grasslands of the Chihuhuan and Sonoran Regions generally extended from portions of Trans-Pecos Texas and Chihuhua across Arizona and Sonora into southern California. Expansion (desertification by invasion of woody plants) of Chihuhuan and Sonoran Desert vegetation onto virgin range on which natural climax vegetation was xeric grassland has resulted in expansion of disturbance climax of desert scrub and corresponding reduction of climax semidesert grasslands. The main outline of original pre-white man and disturbance-retracted margins of the xeric semidesert grasslands were and remain more-or-less conterminous with the semiarid mixed prairie and shortgrass plains grasslands of the Great Plains on the north and east. To the west and south the drier semidesert grasslands are "constant contact" with the various subdivisions of the Chihuhuan or Sonoran Deserts.

The second (and considerably smaller) of the regional semidesert grassland formations is that associated with the "cool" Great Basin Desert and, marginally, the "transition" Mojave Desert. Great Basin semidesert grasslands were considerably smaller and much less frequent in ocurrence as potential natural (pre-Columbian) range vegetation. The widely scattered and smaller semidesert grasslands of the Great Basin occurred between the semidesert grasslands and desert shrublands of the Chihuhuan-Sonoran Regions to the south and the shrub-bunchgrass steppe of the Columbia Plateau to the north. Current generalized distribution coincides roughly with pre-Columbian boundaries as they have been interpreted in studies and maps of natural vegetation. Relatively limited occurrence, along with small and restricted patial scale-pattern, of these dry grasslands is even more so on existing Great Basin range where desertification and expansion of human settlement has been pronounced. In fact--as was explained below--semidesert grasslands of the Great Basin were often completely ignored in detailed treatments of semidesert grasslands. Semidesert grasslands of Intermountain North America were recognized and described briefly by some of the better-known and more experienced students of Great Basin vegetation, but overall these xeric grassland ranges received but a pittance of the coverage given their counterparts to the south.

Burgess (in McClaran and Van Devender [1995, ps. 51-56) briefly reviewed the historical interpretation of the semidesert grassland The closest thing to comprehensive treatment of the semidesert grassland is The Desert Grassland first written by Humphrey (1958) and then updated and expanded under editorship of McClaran and Van Devender (1995). Treatment of this vast and naturally fragmented grassland association or grassland sub-biome remains far from complete. Most coverage of the semidesert grassland has been limited to the geographical al North American Southwest with omission of the "patches" or "fragments" of semidesert grassland found in more northern portions of the Basin and Range physiographic province. For example, in McClaran and Van Devender (1995) there was no mention of the states of Utah, Nevada, or California while Colorado was noted only in regard to shortgrass plains. In fact, this monographic treatment included more grassland of the true prairie than it did of actual semidesert grasslands on the perimeter of the Sonoran Desert (see Figure 1.1, p. 2 in McClaran and Van Devender [1995]). This more eastward interpretation (to the exclusion of more western and northern extensions of the desert plains grassland) followed the earlier outlook by Humphrey (1958). In this same plane, there was no reference in McClaran and Van Devender (1995) to Indian ricegrass (Oryzopsis hymenoides). Yet in this Semidesert Grassland chapter the current authored clearly showed that there definitely are units of semidesert grassland as far north as southern portions of Colorado, Utah, and California, and that Indian ricegrass is a dominant climax species of semidesert grasslands that occur within the larger, surrounding deserts or desert regions.

Clements (1920, ps. 144-149) was one of the first--if not the first--to recognize the semidesert grassland as a major climax unit: the Desert Plains Grassland, the Aristida-Bouteloua Association. Incidentially, in this treatment Clements (1920, ps. 144-149) affiliated the semidesert grasslands with the contiguous and nearly continuous parts of the immense North American grassland formation to the east while ignoring florisitic relations and botanical/ecological influences of the desert formation to the west. From a plant community perspective (especially as a mapping and describing project thereof) this made sense in Clements' time and at the broad spatial scale at which he, of necessity, treated natural vegetation. To a degree this interpretation ignored large "patches" of semidesert grassland found within the western Sonoran Desert and southern Great Basin Desert. Small climax units of semidesert grassland in the Chihuhuan Desert were more readily included--even if by default--in the Clementsian view (which has been continued in works like McClaran and Van Devender [1995], even though they might protest "association" with Clementsian doctrine). This was due to closer proximity of eastern parts of semidesert grassland to semiarid Great Plains grasslands. It was very telling that nowhere in the classic, seminal, monumental treatment of North American vegetation did Clements (1920) refer to Indian ricegrass as species of Oryzopsis, Stipa, Eriocoma, Stiporyzopsis, Piptatherum, Urache, or any other synonym (Hitchcock and Chase, 1950, p. 909-910). With a century's worth of knowledge since Clements (1920) Indian ricegrass has been so recognized for its importance and value as a native species that it was selected as the State Grass of two states (Utah and Nevada).

Historically and traditionally the North American semidesert grassland has been interpreted and delineated much too narrowly.

Technical note on syntax- Deserts are deserts, grasslands are grasslands. One of these biomes cannot be the other anymore than a forest can be a desert. One would never speak of a desert forest. So why use the oxymoron, "desert grassland"? The difference in life form of dominant plants is greater between grassland and desert (herbaceous species vs. woody plants) than between forest and desert (woody plants dominate both). The range vegetation described below is semidesert (a usage deemed to be self-explanatory and one of long-standing precise usage) grassland. Traditional titles in the historic literature such as "desert grassland" and, especially, "desert plains grassland" were shown when such titles were essential in discussion of particular papers or perspectives of specific authors.

It should also be stressed that presence (and designation) of semidesert grassland is more a matter of aridity or extreme semi-aridity than of species composition, physiogonomy, species diversity, etc.of the range plant community. In its less xeric forms (range sites, subtypes) semidesert grassland includes a substantial cover and production of midgrasses, cool- season as well as warm-season species. Such range vegetation has the aspect and species makeup of mixed prairie, including some dominants of the more mesic mixed prairie grassland (Clements, 1920, ps. 144-149; Weaver and Clements, 1938. ps. 525-526). Similarily, desert plains grassland on more drier habitats has the physiogonomy (and many of the same species) of shortgrass plains grasslaqnd. Again, aridity (and features associated with this omnipotent factor) is the determining and distinguishing attribute that differentiates this most xeric grassland from all others.

Semidesert grasslands of the more southern portions of the Basin and Range physiographic province developed both as 1) zonal (likely ecotonal) range vegetation between Great Plains grasslands (mixed and shortgrass prairie range types) and the Chihuhuan Desert as well as mountain grasslands and the Sonoran Desert and 2) vegetational mosaics of grassland and among Chihuhuan and Sonoran shrubland (desert). Thus spatial distribution and pattern of Chihuhuan and Sonoran semidesert grassland range varies from broad bands or belts (zonal vegetation occupying relatively large terrestrial space) to "patches" or a "patch-work" dispersed within the overall surrounding desert scrub. The latter spatial arrangement in context of Landscape Ecology consist of semidesert grasland patchs in a desert matrix. It was explained previously that the spatial extent to which Chihuhuan and Desert Desert vegetation has invaded (encroached upon or replaced) pre-Columbian climax semidesert grassland is unknown. Scientific or empirical evidence (research), which has been consistent with anecdotal evidence (eg. land surveyer notes, rancher accounts, explorer and traveler diaries), has conclusively shown that there has been (in some instances continues to be) extensive desertfication and loss of grasslands to scrubland (desert).

There is considerable variation within the Chihuhuan-Sonoran semidesert grassland complex. Unfortunately the extent and kind of this variation, especially as to various grassland communities as reflected in range cover (= dominance) types, was not presented in recent ecological works on the subject as for example in hoped-for encyclopedic coverage in The Desert Grassland (McClaran and Van Devender, 1995).

8. Devil in the desert grassland- Plant of devil's claw or unicorn plant (Proboscidea parviflora= P. louisianica= Martynia louisianica) with both flowers and fruit. Devils' claw has been included in the the sesame family, Pedaliaceae (Great Plains Flora Association, 1986, p. 803; Diggs et al., 1999, ps. 879-880), or its own unicorn plant family, Martyniaceae (Steyermark, 1963, p. 1372). Devil's claw is a widely distributed plant being found growing naturally from Texas and Mexico westward to the Mojave and Sonoran Deserts of California. In addition, unicorn plant has naturalized widely across North America being found from Pennsylvania to Louisiana which might (or might not) be part of its original species range. Unicorn plant conceivably could have spread perhaps due to cultivation for its fruits which are used as a type of pickle (all the above sources made note of this fact).

Devil's claw does best on drought to xeric habitats. This individual shown here was growing in the West Cross Timbers of northcentral Texas in the worst one-year droughts on record.

College Farm, Tarleton State university, Erath County, Texas. Late September; full-flowering to fruit-set stages.

9. Devilish details- Devil/'s claw or unicorn plant shown with flowers, leaves, current year's fruit and last year's fruit (first slide). Details of the unusually colored flower with a backdrop of its leaves were presented in the second slide. Plants of this species are typically annuals though some individuals are short-lived perennials. This plant had been grazed (lightly in this case) by white-tailed deer (Odocoileus virginianus). In a summer of Exceptional Drought (Palmer Severity Index rating of D4) deer had grazed most devil's claw plants on this range into oblivion. This and two other plants were the only ones of dozens that the author found to left to photographed (damn deer getting in the way of education).

College Farm, Tarleton State university, Erath County, Texas. Late September; full-flowering to fruit-set stages.

10. Last year's and this year's crop- The picturesque fruit of devil's claw or unicorn plant. Green (immature though ripening) fruit at left accompanied by a dried and split-open fruit from the preceding year at right. This fruit was described in detail by the Great Plains Flora Association (1986, p. 803) as "...drupaceous capsule, bivalved and dehiscent" T he author had had many of these dried fruits wrap around his boot heel on the New Mexico State University College Ranch, especially on desertified semidesert grassland. This fruit had been produced in the West Cross Timbers of northcentral Texas during the worst one-year drought on record.

College Farm, Tarleton State University, Erath County, Texas. Late September.

Technical note: the next five sets of paired photographs compared JPEGs made from 35mm Kodachrome slides by an Epson Perfection V700 Photo color scanner (photographs on left) and a Hewlett-Packard Scan Jet 7400C-Scan Jet XPA color scanning unit (photographs on right). Color was most accurately reproduced by the Epson Perfection V700, but this Epson unit produced (added) an unnatural "sparkle" or "frosted" appearance to the foliage which the Hewlet-Packard Scan Jet 7400C did not add. Conversely, the Hewlet-Packard unit added a bluish-tone to foliage that the Epson did not.

Conclusion: neither the Epson Perfection (perfection it most certainly is not) with its additional "shotgun-shot sparkle" nor the Hewlet-Packard Scan Jet with its added scanned bluish tinge were completely satisfactory for the task of scanning with accurte color. Likewise, both of these cheaply made, imprecise pieces of equipment automatically cropped edges of slides. The only reason that the author used these pieces of "gyp-aggo" apparatus was that they are about all that is available for scanning decades-worth of slides taken prior to introduction of digital imaging (which incidentally has myriad problems of its own as well).

Science (education, in general) alsways involves trades-offs and compromises.

11. Tobosagrass clay flat on an ecotone- A small tobosa swale situated among larger areas of ridges in a transition zone (an "overlap" area) among western Rio Grande Plains, eastern edge of Trans-Pecos Basin and Range, and marginal contact with semiarid Edwards Plateau. There has been inconsistent mapping of vegetational (= land resource) areas of Texas (Gould, 1962, ps. 1, 11; Correll and Johnston, 1979, map 1, ps. 9-10, 12), potential natural vegetation (Kuchler, 1964, map in Garrison et al., 1977), and Texas level III ecoregions (Griffith et al., 2004) with respect to western boundary of Edwards Plateau and eastern boundary of Chihuhuan Desert. This tobosagrass flat and surrounding stand of honey mesquite, huisache (Acacia farnesiana), and Texas persimmon (Diospyros texana) were on range that was included in the western Edwards Plateau by (Gould, 1962, ps. 1, 11; Correll and Johnston, 1979, map 1, ps. 9-10, 12), but in the eastern contacts of Chihuhuan Desert according to (Kuchler, 1964, map in Garrison et al., 1977) and (Griffith et al., 2004). There was not even one single plant of creosotebush (Larrea tridentata) in the range vegetation shown here so designation of this range plant community as being in the Chihuhuan Desert was not overly plausable.

The swale or clay flat supporting a consociation of tobosagrass did provide some textbook examples of this range plant community (even if it was a small parcel of grassland) that was used for instructive purposes (with qualifications duly noted). For practical illustration of the tobosagrass-dominated semidesert grassland the designations of vegetational units were consistent with those cited above. FRES No. 40 (Desert Grasslands Ecosystem). K-48 (Gramagrass-Tobosagrass Prairie). Not specifically described by SRM cover type; variant of SRM 505 (Grama-Tobosa Shrub). Tobosa Grass-Scrub Series 143.12 of Chihuhuan (Semidesert) Grassland biotic community 143.1 of Brown et al. (1998). Level III ecoregion of Texas was transition between Chihuhuan Deserts and Playas Ecoregion 24a of Chihuhuan Deserts and Semiarid Edwards Bajada Ecoregion 31b of South Texas Plains (Griffith et al., 2004).

Val Verde County, Texas. October, phenological stage of tobosa varied from anthesis through grain-ripe to grain-shatter.

12. "And the green grass grew all around, all around; and the green grass grew all around" (American folk song)- Characteristic sward of tobosagrass on a swale showing the semi-cespitose habit of this rhizomatous perennial eragrostoid grass. Individual plants of tobosagrass typically grow in close proximity to each other so as to form an open sod or turf, especially on more mesic habitats (eg. swales and larger bottomland sites), so that stands of tobosa have a bunchgrass-like appearance. This is in contrast to the "kissin' cousin", curly mesquite (H. belangeri), which is stoloniferous and forms a more nearly closed turf or complete sod.

This small stand or consociation had been lightly grazed by cattle such that individual plants and the open sod or turf were more obvious. These photographs were "picture perfect" examples of proper degree of use, which in the semiaridity or aridity of this range environment was on the light side of moderate. This range professor reminded his student readers that moderate grazing (= defoliation) is not automatically synonymous with proper grazing any more than is light or heavy degree of grazing defoliation proper or improper. Proper use factors are not only species-specific, but even site-specific for species-specific standards or guidelines. A key diagnostic guide to proper degree of use (the first and usually the most important of the Four Cardinal Principles of Range Management) is presence of individual shoots that were ungrazed and, usually, matured to flowering and grain production. Reproduction of perennial grasses like tobosa is usually asexual (by tillers and rhizomes in H. mutica) so seed production is not necessary nor usually important for regeneration of this valuable climax species (decreaser on swale sites). Rather, presence of sexually reproductive shoots is a very good sign to graziers that the tobosagrass range was properly managed as to degree of use. Plus, this degree of grazing defoliation with subsequent seed-set best provided for the option of establishment of seedlings that can fill in interspaces among existing tufts of older plants. Seedling establishment permitted presence of new genotypes (the opportunity for on-going genetic adaptation) of this remarkable and valuable semidesert species.

Val Verde County, Texas. October, phenological stage of tobosa varied from anthesis through grain-ripe to grain-shatter. FRES No. 40 (Desert Grasslands Ecosystem). K-48 (Gramagrass-Tobosagrass Prairie). Not specifically described by SRM cover type; variant of SRM 505 (Grama-Tobosa Shrub) variant. Tobosa Grass-Scrub Series 143.12 of Chihuhuan (Semidesert) Grassland biotic community 143.1 of Brown et al. (1998). Level III ecoregion of Texas was transition between Chihuhuan Deserts and Playas Ecoregion 24a of Chihuhuan Deserts and Semiarid Edwards Bajada Ecoregion 31b of South Texas Plains (Griffith et al., 2004).

13. Beautiful, and outstanding example to boot- Individual plant of tobosagrass that was grazed during current growing season to proper degree of use as determined by general qualitative appearance, but not on specific quantitative guidelines (assuming that such even exist). Key features of proper grazing included: 1) adequate photosynthetic tissue (both leaves and culms) remaining following grazing, 2) some shoots that were permitted to mature to sexually reproductive (= flowering) stage, 3) irregular, domed shape of grazed plant rather than a heavily cropped one having a flat, highly hedged appearance, and 4) overall degree of utilization (composite of defoliation for whole plant) that was somewhat on light (conservative) side of the total or maximum utilization that would enable the plant to survive. In regards feature #4, management of this tobosagrass range was such that some "surplus" feed was left for an emergency, risk, etc. that might befall plant, animal, or ranching firm. The conservative or cautious grazing use would come closer to permitting higher levels of herbage production under environment stress, especially drought. The rangeman responsible for husbandry of this range had hedged his bets and left "a little extra" grass just in case "things get tight". Such wise stewartship is good ranch as well as good range management.

The rest of the explanation for the bountiful flowering of tobosa on this range as shown in these photographs was an extremely wet late summer and early autumn. Numerous, well-spaced showers and cool temperatures resulted in near ideal soil moisture conditions. Students take note: even abundant rainfall and other features of a fabulous plant-growing environment would not have permitted the profuse flowering and lush foliage of this tobosagrass had it been grubbed to the ground by overuse. Vice versa, even if growing conditions had been adverse for tobosa on this swale there would still have been some sexual reproduction in the stand given the wise use management--especially proper degree of utilization--it received.

Val Verde County, Texas. October, phenology ranged from anthesis to grain-shatter stages.

14. Nothing much purtier to a desert grassman- A large speciment of tobosagrass at peak bloom on a swale in Rio Grande Plains savanna-Chihuhuan Desert ecotone. This plant had been properly grazed (defoliation of outer edge of grass still evident in foreground) and, with blessings of late-growing season rain showers, a high number of shoots had developed to sexual maturity.

Val Verde County, Texas. October. On this one plant phenological stage varied from anthesis through grain-ripe to grain-shatter (with more soil water from each new shower ever more shoots advanced to flowering stage).

17. Ring muhly or ringgrass (Muhlenbergia torreyi)- This cespitose grass grows on plains and mesa grasslands of the Great Plains through the semidesert plains grasslands of the Trans Pecos Basin and Range province. As indicated by it's common name ring muhly exhibits a unique growth habit. This bunchgrass produces secondary shoots only in the form of tillers such that asexual reproduction takes place around edges of the existing mother plant. The result is an ever-expanding circular pattern of growth. When the oldest tillers (mother and first daughter shoots) that were in the center of the plant were shed (ollowing their senescence and death) the result was a "ring" of tillers. Ring muhly shoots often have characteristically curled leaves.

Ring muhly is a common but not a major forage-producing species. It is, however, often readily taken by livestock. Ringgrass is undoubtedly valuable for erosion control and watershed protection. It's growth pattern was an apt illustration of the concept of clonal organism.

21A. Black grama semidesert grassland in "mint condition"- With proper management-- in this case, limited to proper grazing management--even after a decade or more of severe drouth this vegetation was still as virgin as it gets. Species composition, community structure, and ecosystem function was the same as if human eyes had never rested on it. This was almost a single grass species-community with sparsely scattered evergreen shrubs. There were also scattered individual plants of sideoats grama (like the larger cexpitose grass plant in center foreground) and cane bluestem. Tobosagrass grew on the isolated microsites of small depressions in the land surface.

Students were again reminded that black grama semidesert grassland is by far the most common kind or form of what has traditionally been called "desert grassland. Black grama is the regional or zonal dominant grass of the greater Chihuhuan-Sonoran Deserts Basin and Range Region.

Presidio County, Texas. June, early estival aspect prior to onset of summer rains. FRES No. 40 (Desert Grasslands Ecosystem). K-48 (Grama-Tobosa Prairie). SRM 505 (Grama-Tobosa Shrub). Grama Grass-Scrub Series 143.11 of Chihuhuan (Semidesert) Grassland biotic community of Brown et al. (1998, p. 40). Chihuhuan Deserts- Chihuhuan Desert Grasslands Ecoregion, 24 b (Griffith et al., 2004).

21B. Species diversity on "perfect" black grama semidesert grassland- Species diversity on the black grama form or expression of semidesert grassland is typically very low. It is a classic Clementsian consociation across vast areas. Other grass (and a few forb) species are present, but in small to almost trace amounts. Two of the more frequent of associate grass species include sideoats grama--State Grass of Texas--, which was conspicouosly dominant locally in the foreground, and cane bluestem, the conspicuous, somewhat decumbent grass with larger shoots in center midground. Both sideoats and cane bluestem are mid-grasss species (in contrast to shortgrass species like black, hairy, and blue grama). Given presence of both mid- and shortgrasses this range vegetation could be described precisely as "mixed prairie", but that designation as a proper title has usually been reserved for Great Plains grassland communities that also often include tallgrass species. Kuchler (1964, in Garrison et al., 1977) entitled this range type "prairie". It fits.

"Savannah" would be another arbitrary distinction that could be used to describe this range vegetation, specifically to characterize for instructive purposes presence of woody plants (the larger of which have a tree-like form). In this author's judgment, semidesert grassland is-- as historically described by the word "grassland"-- a true grassland (ie. vegetation and a range cover type in the grassland biome). Dick-Peddie (1993, p. 107) cited other workers who described this vegetation as a "shrub-steppe" . It is important for those new to this range vegetation to understand that presence of the soaptree yucca so prominent in this photograph and longleaf joint-fir or longleaf Mormon tea (Ephedra trifurca) are indicator and defining species to climax black grama semidesert grassland. Dick- Peddie (1993, ps.116 ) carefully explained this key floristic feature. That key botanical phenomenon was underscored here and now by the current author as well.

Presidio, County, Texas, early estival aspect prior to convectional summer rains. FRES 40 (Desert Grasslands Ecosystem). K-48 (Grama-Tobosa Prairie). SRM 505 (Grama-Tobosa Shrub). Grama Grass-Scrub Series 143.11 of Chihuhuan (Semidesert) Grassland biotic community of Brown et al. (1998, p. 40). Chihuhuan Deserts- Chihuhuan Desert Grasslands Ecoregion, 24b (Griffith et al., 2004).

21C. Black grama-dominated semidesert prairie- Soaptree yucca, State Flower of New Mexico, is an indicator of climax semidesert grassland of the black grama form (Dick-Peddie, 1993, ps. 131-132) and presents a savanna-like physiogonomy to this wonderfully adapted range vegetation. The semi-open sward seen in this and the next photograph is also a obvious physionomic characteristic of semidesert grassland, especially of the black grama form. As shown in photographs below, black grama, like tobosagrass, spreads (often vigerously and extensively) by stolons. The semiaridity of climate and xeric nature of soils is such that the soil surface is not covered to the extent that it is in more mesic areas and with other stoloniferous species like buffalograss (Buchloe dactyloides) or even the larger rhizomatous bunchgrasses. Buffalograss, blue grama, bush muhly, mesa dropseed, and perennial threeawns are typically present even on virgin state black grama range like this one, but their overall density and cover is miniscule other than at microsite scale. A high percentage of these grass species (eg. bush muhly, mesa dropseed, and threeawns) are strictly cespitose and produce no stolons.

Presidio County, Texas. June, early estival aspect (prior to summer rains necessary for meaningful "green-up"). FRES No. 40 (Desert Grasslands Ecosytem). K-48 (Grama-Tobosa Prairie). SRM 505 (Grama-Tobosa Shrub). Grama Grass-Scrub Series 143.11 of Chihuhuan (Semidesert) Grassland biotic community of Brown et al. (1998, p. 40). Chihuhuan Deserts- Chihuhuan Desert Grasslands Ecoregion, 24b (Griffith et al., 2004).

21D. Overall appearance of black grama-dominated semidesert grassland range- This climax vegetation illustrated physiogonomy and botanical compostion produced by presence of both herbacesou and woody species. In addition to soaptree yucca, longleaf Mormon tea or joint-fir was prsent in this slide. The herbaceous layer was "pure" black grama and the sward had the patchy or spotty appearance produced by this species. (Even though black grama reproduces to large degree via stolons this species still creates a semi-open herbaceous canopy.)

Dick Peddie (1993, ps. 116, 131-132) explained that presence of certain diagonostic (= indicator) species on what was Chihuhuan Desertscrub provided evidence that the vegetation had been semidesert grassland which had most likely been converted to desert by human-induced shifts in vegetation. Indicator species included longleaf Mormon tea (in contrast Torrey Mormon tea [Ephedra torreyana]), desert holly, and fluffgrass (Triens pulchellus). Presence of both soaptree yucca and Mormon tea added another layer to this range plant community and resulted in rang vegetation that had a savanna-like appearance and a shrub-steppe physiogonomy. These evergreen, narrow-leaved shrubs also produced a unique visual aspect to the vegetation.

Presidio County, Texas. June, early estival aspect (prior to onset of summer rainy season). FRES No.40 (Desert Grasslands Ecosystem). K-48 (Grama-Tobosa Prairie). SRM 505 (Grama-Tobosa Shrub). Grama Grass-Scrub Series 143.11 of Chihuhuan (Semidesert) Grassland biotic community of Brown et al. (1998, p. 40). Chihuhuan Deserts- Chihuhuan Desert Grasslands Ecoregion, 24b (Griffith et al., 2004).

22. Sward of black grama (Bouteloua eriopoda) - Outward physical appearance of a sample of a stand (= a colony might be more appropriate) of black grama. On a lightly grazed (by cattle) range that was in Excellent range condition class at the end of first growing season following the Long Drought of the 1990s through early 2000s. Many of the eragrostoid (= chloroid) grass species (those in Gramineae subfamily, Eragrostoideae) have shoots that live for more than one growing season (ie. have aboveground living tissue that persists for two or more years). This is not to be confused with the biennial life cycle (they are perennial species) or with semi-woody (either suffrutescent or becoming woody) plants. Rather, some shoots of some of these grasses under certain growing conditions simply do not die completely and instead maintain some meristematic tissue in culms or buds. Plants of certain grass species enter (or persist) into a condition that might be described as "semi-dormancy" from which they are able to emerge and (or in which they) "green-up" (ie. produce new tissue that is soon capable of photosynthetsis). This is undoubtedly an evolved opportunistic adaptation for survival under sporadic growing conditions such as aridity, periodic heavy precipitation, widely fluctuating temperatures, etc.

Plants in such a state of "suspended perenniality" (to coin a purely descriptively instructive term) not only respond quickly to episodes that are favorable for growth and/or reproduction, they also retain biomass of higher nutritive value (in contrast to the nutritionally leached herbage of plants and species that do not maintan such tissue and instead "die back to the ground" at the end of each growing period. This is a major reason why available herbage of most panicoid grasses like Andropogon, Bothriochloa, Panicum, and Paspalum species is less nutritions and palatable than that of of some eragrostoid grasses like certain species in Bouteloua, Chloris, and Spartina. Biomass of buffalograss also falls in this latter group.

The phenomenon just described can be visually observed by the "looks sorta green" (pale or "dim" green or gray-green) color of shoots of these species (again, at least under certain conditions). This condition and coloration was readily seen in the black grama shoots shown in this slide. Even though summer rains had not commenced at time of photographing these plant there was enough residual soil moisture (from winter and spring precipitation) that lower parts of last year's shoots were still partly green. This plus new growth of this year's young shoots provided the coloration shown here. (This is another reason for using non- or low-color enhancing film or neutral film like Kodachrome.)

Students should also take note of the open appearance of black grama sward. Black grama is not a cespitose (bunchgrass) species. Instead it is stoloniferous and a sod-forming grass. Black grama reproduces asexuallly by tillers as well as stolons but the resultant growth pattern and appearance is of an open or patchy sod with substantial bare soil among dense "clumps" of a perennial grass that spreads most effectively by runners (stolons).

23. Plant of black grama or wooly grama- This "plant" of black grama consist of a larger "clump" (group of tillers) behind three smaller "clumps". The three smaller "bunches" are clones or modules ("daughter plants") produced asexually from the larger "parent" (or "mother") plant, the latter of which was almost undoubtedly a "daughter plant" from its "parent plant". Assuming that the "parent" of the "daughter plants" was itself a clone or module of a preceding parent, each of these vegetatively or asexually produced "plants" (each module) was a ramet of one genet, the original genetic (sexual) individual. This illustrated a modular organism. Only the genet, the plant produced by sexual reproduction (exchange of gametes) was a unique or "one-of-a-kind" organism. How many years, decades, or, even, centuries ago this sexually generated ancestor came into existence is known but to God.

Black grama reproduces by seed (from a caryopsis) very rarely. Prof. Ken A. Valentine spent over forty years involved in research on the Jornada Experimental Range and New Mexico State University College Ranch. Valentine (personal communication) claimed that he had never seen a single black grama seedling.

Presidio County, Texas June.

24. Shoots of black grama- Another common name for Bouteloua eriopoda is wooly grama. This basis for this descriptive name was the abundant pubescence on the internodes (hence, wooly or fuzzy stems). This pubescence and a unique shade of green color on the culms is the distinctive idenfiying feature of this regional dominant and extremely valuable range plant.

Big Bend Ranch State Park, Presidio County, Texas. June.

25. Detail of black or wooly grama shoot- Some sheaths on black grama shoots cover (enclose) almost all of the internode of the culm. While rangemen refer to the wooly "stem" of wooly grama it is actually the wooly leaf. Leaves are frequently absent or missing from portions of black grama shoots thus exposing the culm that is often a light yellow color. This alternating green and yellow color pattern was visible in the preceding slide. Interspersed with the green and yellow pattern of living shoots is the dull gray color of dead-but-still-attached shoots like the one featured in this shot. This shoot was a tiller, a vertical or upright intravaginated shoot.

Presidio County, Texas. June.

26. Black grama runners- In contrast to the tiller in the preceding photograph, a runner (stolon is the scientific term) is a horizonal extravaginated shoot. In this photograph two stolons were laying atop and across a third (though less visible) stolon. All three stolons were living, but as is often the case for shoots of this species they looked "more dead than alive". Three nodes with emerging new clones or modules (appearing as buds) were visible. Plants were just initiating new growth at onset of summer rainy period.

Presidio County, Texas. June.

27. "Throw out the life line"- True to the words of the old hymn by E.S. Ufford black grama has grown the life line for another generation of this mostly clonally reproducing mainstay of the semidesert grassland ranges. Several stolons were visible on the surface of this sandy semidesert soil. A large module or ramet was developing from the node of the foremost runner. This "daughter plant" was shown in more detail in the second slide.

Presidio County, Texas. June.

28. "Putting down roots" or "a hen and two chicks"- Two stolons from an established black grama plant have each produced a "new plant" (a module= clone= ramet). Each "daughter plant" became established (one or maybe two growing seasons prior) and was waiting for rain at beginning of the summer rainfall period. Summer is when most precipitation occurs in the climate of the Trans-Pecos Basin and Range.

New modules were developing on another stolon (to left of established ramets) to be ready for next summer's rain.To a range plant and a rangeman, "There's always next year". The asexual reproduction shown here took place during last phases or just after one of the most severe droughts in weather records. Grazing management must allow for such reproduction: "Take care of the grass and it will take care of you".

Presidio County, Texas. June.

29. Inflorescences of black or wooly grama- The infloresecence type of eragrostoid grasses (those in subfamily, Eragrostoideae) is a raceme. Spikelets are borne on pedicels on the rachis (adjective, pedicellate). That black grama produces grain was shown here; that such grain is less productive of new black grama plants was shown in preceding photographs of asexual reproduction.

Presidio County, Texas. June. (Spikelets had persisted on the rachis throughout course of winter and spring suggesting to any range-wise rangeman that there had been but scant precipitation.)

30. Mesa dropseed (Sporobolus flexuosus)- Local stand of mesa dropseed. This is one of the most common and important species on recovering black grama range (deteriorated range undergoing plant succession). Mesa dropseed appears to respond to disturbance primarily as an increaser (Pieper and Beck,1990), but on many, if not most, range sites in the semidesert grasslandmesa dropseed is an important component of the climax range vegetation (Soil Conservation Service, undated; range site descriptions). Mesa dropseed is especially important on depleted black grama range that was converted into Chihuhuan Desertscrub disclimax. On such "man-made" deserts mesa dropseed may be a major grass species along with the less palatable perennial threeawns and the palatable bush muhly which frequently grows near creosotebush.

Elephant Mountain Wildlife Management Area, Brewster County, Texas. June, early new growth ("green-up") at beginning of summer rainy period.

31. Individual plant of mesa dropseed- Specimen of mesa dropseed with the "sprawling" habit frequently developed in this species. The twisted or rolled leaves are a common characteristic of Sporobolus species. The grass's "next door neighbor" was the invasive, but short-lived suffrutescent composite, broom snakeweed.

New Mexico State University College Ranch, Dona Ana County, New Mexico. June, early new growth ("green-up") at onset of summer rainy period (dead plant material was biomass produced the previous summer).

32. Mesa dropseed (Sporobolu;s flexuosus)- Whole plant--shoots; aboveground portion-- of mesa dropseed (first slide) and details of shoots (second slide) of mesa dropseed, the principal increaser on many degrated former black grama-dominated semidesert grassland ranges. All conspicuous plant parts (all but small green basal and the few green adult leaves) were produced the preceding summer-fall growing season. The bent or flexuous leaves are a feature common to most Sporobolus species, but apparently they were so prominent in this specific species as to serve as basis for the specifid epithet.

The deep sandy soil of this mesa dropseed specimen probably was the edaphic basis of a black grama semidesert grassland ecosystem that was largely replaced by the adjacent but distinct Chihuhuan Desert due to human action. This location was directly on the El Camino Real, the first European road in North America (ran from Santa Fe to Chihuhua City). Grazing by draft animals (horses, mules, asses, oxen) used for trade and travel along this route for nearly 300 years was the most probable cause of human-induced desertification.

On such drastically altered landscapes and ecosystems mesa dropseed is a keystone species, and the key to whatever recovery of vegetation, soil etc. is possible.

New Mexico State University College Ranch, Dona Ana County, New Mexico. June, plant organs were of both the previous growing season and the first part of current growing season.

33. Local stand of sixweeks grama (Bouteloua barbata)- On this spot (microhabitat) several plants of the ephemeral sixweeks grama had germinated and just completed their short life cycle. Sixweeks grama is one of the few annual grass species that is native to semidesert grassland and desertscrub in the Chihuhuan Region. Perenniality is a major plant adaptation to harsh environments like desert, alpine, saline, and rocky ecosystems. Under severe disturbance (eg. anthropogenic causes that highly modify natural habitats) plant species with the annual life cycle pattern become more competitive with those having biennial and perennial life cycles. This is the concept of therophytes. Therophyte refers to one of Raunkiaer's life form groups that has the annual or ephemeral life cycle so that growth and sexual reproduction are completed quickly during short periods when conditions are favorable and that then survive unfavorable periods as seed or fruit.Therophytes are typical of deserts, especially disturbed desert habitats, tilled land, and overgrazed pastures. The seed or fruit is the plant organ most capable of surviving severe stresses like extreme temperatures, dryness, and long periods of dormancy. Therophytes are usually pioneer species on severely disturbed land. This initial repopulation of plants is essential to plant succession to facilitate invasion and establishment of plant species of higher successional order. Facilitation is the contemporary term for the preceding synonymous term of reaction proposed by F.E. Clements.

On almost all overgrazed ranges of about every range type annual plants become more plentiful with continuing retrogression, the retrograde movement of a biotic community toward communities of lower succeessional order (= lower seral stages). With continuing retrogression annual or ephemeral species often become community dominants. The sixweeks grama plants shown here were growing on land that had been a main trail along El Camino Real, the oldest European road in North America, that had been subjected to about every human activity imaginable, not least of which was livestock grazing. Climax dominants like black grama and tobosagrass were displaced by plant species of lower successional order as range retrogression moved climax black grama semidesert grassland to anthropogenic Chihuhuan Desert. The rangeland at this location is at static or maybe upward range trend as human disturbance has been reduced or eliminated. Sixweeks grama was doing "yeoman's service" to improve the range.

Under such successional conditions annual and ephemeral species-- at least native species-- are not weeds. They are essential for healing of the range. Ephemerals and annuals are as ecological invaders because they do invade and colonize disturbed rangeland. The diagnostic successional designation of invader does not always imply noxious plant. Yes, under many conditions invader certainly may mean weed or brush, but when the impacts of invaders are those of beneficial reaction (= facilitation) benefits of invaders exceed their adverse impacts. If such ephemerals are weeds they are virtuous ones.

Ephemeral in this usage refers to annual plant species that have especially short life cycles.Ephemeral grasses are often called "sixweeks grasses". Another "sixweeks grass" that is native to the semidesert grassland range type is sixweeks threeawn (Aristida adscensionis). It is usually less common than sixweeks grama on sandy soils.

New Mexico State University College Ranch, Dona Ana County, New Mexico. June, seed-shattter stage of phenology.

34. Sixweeks grama (Bouteloua barbata)- Example of one of the most common ephemeral grasses on degraded semidesert grassland and Chihuhuan Desert ranges. This specimen had just had its moment in the sun: it recently completed its short life cycle culminating with shedding of grain. It had achieved the ultimate biloogical success: it reproduced and propagated its kind. The amber color of these plants (captured by ever-true color Kodachrome) is typical of most annual grasses.

On an old trail of El Camino Real, New Mexico State University College Ranch. Dona Ana County, New Mexico.June, seed-shatter phenological stage.

35. Bush muhly or hoe grass (Muhlenbergia porteri)- Along with black grama, bush muhly is one of the most palatable--hence most apt to be grazed out--climax grass species of the semidesert grasslands. In western, more xeric areas of the Chihuhuan Region bush muhly is an associate to black grama. Bush muhly is frequently observed to grow in association with and even outcompete creosotebush on the Chihuhuan Desert-semidesert (Chihuhuan) grassland ecotone. The phenomenon (complete with photograph) was described in the Chihuhuan Desert chapter herein. Powell (2000, p. 177) stated that the common name of bush muhly was derived from the association of this palatable species with protection-providing shrubs. That is logical, but the bush-resembling general appearance of this grass would also seem a likely origin of the adjective, "bush". Whitfield and Anderson (1938, p. 174) stated that bush muhly "... forms bush-like masses". Whitfield and Anderson (1938, p. 174), Gould (1951, p. 201-202), and Humphrey (1960. ps. 67-69) remarked that in the origina range vegetation (prior to advent of ranching) bush muhly was extremely abundant, but that this extremely palatable native grass was at time of their writing found almost entirely under protection (presumedly from excessive livestock) of shrubs.Wooton and Standley (1915, p.69) listed the common name of M. porteri as "mesquite grass" (obviously a confusing name) because in southern New Mexico where it was so common "... it is nearly always found growing in the shade of mesquite bushes ...", but even then cattle "...will force their way into the mesquite to reach the grass". The relationship between bush muhly and woody plants was unclear from the descriptive literature.

The common name of "hoe grass" (Whitfield and Anderson, 1938, p. 174; Humphrey, 1960, p. 67) was even more intriguing than origin of the adjective, "bush". Numerous of the semidesert grassland grass species were harvested and sold for hay. Such hay was mostly black grama, chino grama, and tobosa, but it is likely that any grasses associated with these were also used for hay. "Hoe" could have been in reference to hay harvest.

El Paso County, Texas. June.

36 Another example of bush muhly- This specimen was growing in the Trans Pecos Basin and Range province on an ecotone between semidesert grassland and Chihuhuan Desert. The fiercely competitive feature of bush muhly was evident from this plant that was growing around a plant of tarbush (Florensia cernua) which had died as a result of grass-shrub competition. Observant students will note that there were four (or five) live plants of tarbush growing in close proximity around the dead tarbush. These live tarbush plants did not have to compete with bush muhly (= other tarbush plants did not have tarbush growing with them).

Railway Ranch, Upton County, Texas. Mid-October; muhly was entering winter-dormancy. .

37. Shoots of bush muhly- Detail of shoots on the bush muhly plant shown in the preceding slide. The decumbent-and-geniculate combination shape of bush muhly shoots allows ready idenftification of this species. Unfortunately, after several seasons or even years of weathering certain plants of black grama and even tobosagrass closely resemble bush muhly. Younger and active-growing plants of bush muhly have a conical habit or even a pyramidal-shape. Both dead (or apparently so) and live (green) shoots on this plant were readily visible in this photograph.

El Paso County, Texas. June, at beginning of summer rain season.

39. Burrograss (Scleropogon brevifolius)- One of the least palatable (and best disturbance-adapted) perennial grasses on semidesert grassland and Chihuhuan Desert ranges is this monotypic genus. Burrograss typically a dioecious (less commonly a monoecious) species, but with several perfect florets within pistillate spikelets and the whole inflorescence being viewed as a contracted panicle or spicate raceme (Gould, 1975, ps. 240). Staminate spikelets are below pistillate spikelets, an arrangement termed gynaecandrous (Shaw, 2008, p. 181).

Burrograss has a large and discontinuous species range that extends from the Sonoran and Mojave Deserts in California and Nevada, semiarid grasslands of Colorado (Shaw, 2008, p. 181) south into Chile and Argentina in South America (Gould, 1975, p. 242)

40. Fluffgrass (Tridens pulcehllus= Erineuron pulchellum= Dasyochloa pulchella; taxonomists better make up their minds on this one's name because they are running out ways to modify the root pulchel.)- This is one of the smallest, lowest stature perennial grass species on semidesert grassland. Fluffgrass has traditionally been interpreted as an ecological invader being lumped in the same company as annual grasses and forbs, most threeawns, and small perennials like red grama (Bouteloua trifida).

There is a twist to this oft-told story however. Dick-Peddie (1993, ps. 132) felt that fulffgrass served as an indicator species much like desert holly (explained above). Either of these herbaceous species might be relict species of semidesert grassland such their presence on Chihuhuan Desertscrub would indicate a desertscrub disclimax. While general occurrence of fluffgrass (and desert holly) was a very small (perhaps trace) proportion of climax semidesert grassland types (eg black grama grassland) this density, cover, etc. was extremely important as a clue to potential natural (= virgin= pre-Columbian) vegetation. Such is the value of an indicator species. It need not be a dominant, associate, or otherwise major species, just a diagnostic one.

El Paso County, Texas. June.

41. Fluffgrass at peak standing crop (such as it was)- This happy little semidesert dweller was "all swole-up" with the pride of any new parent. The "fluff" is the cottony pubescence on mature spikelets. Spikelets are arranged in fascicles, a term denoting a cluster or bunch as applied to culms, leaves, or, as in this instance, inflorescence branches (Gould and Shaw, 1983, p. 374). .Here again this enigmatic little range plant had another twist to its tale. The clumps of the inflorescence (fascicled spikelets) were themselves on clumps or bunches of shoots (and developing roots) that arose from stolons branching out from the parent plant. The little bunches of shoots topped with fascicles were ramets from the main (parent) plant which was an apparent genetic individual or genet. Each flowering module or clone was reproducing sexually (ie. there was prounced asexual and sexual reproduction simultaneously in the same generation).

In the theory of natural selection (= survival of the fittest) fitness is defined as the capacity to reproduce, specifically to reproduce deoxyribonucleic acid (DNA). The fittest organism (genotype, species, etc).is the one that reproduces the most offspring to perpetuate that genotype, species, etc., and that DNA. Increased fitness (more offspring; more DNA) can only come through genetic change. This requires recombination of genes which can only come from exchange and union (fertilization) of gametes (ie. sexual reproduction). The truest reproduction of existing superior genotypes (DNA having superior fitness) comes from cloning, which in plants is vegetative or asexual reproduction.

The fluffgrass plant shown here was hedging its bets and reproducing by both means so as to: 1) optimize the chances of producing improved genetic individuals (genets) and 2) perpetuation of proven (environmentally tested) genotypes through clones (ramets). And that was as good as the brushed twitch of any treasured tail.

The details of this phenomenon were readily visible in the second slide. Cute, hugh?

Presidio County, Texas. June, full-bloom phenological stage.

44. Longleaf joint-fir or longleaf Mormon tea (Ephedra trifurca)- Presence of this plant on a sandy loam plain range that had remnant patches of black grama and scattered plants of tobosagrass, bush muhly, and fluffgrass was successional evidence that this rangeland had once been black grama-dominated semidesert grassland. The range vegetation was a Chihuhuan Descrub disclimax (Brown et al., 1998). For over two centuries before it was surveyed by the US General Land Office this land was on El Camino Real, the first European road in North America (linked Santa Fe to Chihuhua City). After occupation and domination by Anglo culture this rangeland was part of the Public Domain and subjected to open range ranching.

The pre-European (climax) vegetation in this area was a mosaic of black grama-tobosa semidesert (Chihuhuan) grassland and Chihuhuan Desertscrub with large patches of "overlap" (ie. ecotone; ecotonal vegetation). At larger (say, landscape or even regional scale) the virgin vegetation of this entire region was interpreted and mapped as Desert-Grassland Transitionis (Shreve, 1917). Is it any wonder that after 300 years of what assuredly was overgrazing (first by beasts of burden along a trade-travel corridor that was followed by a Public Domain grazing commons) the range ecosystem was converted byr semidesert grassland to Chihuhuan Desert?

Based on evaluations of range analyses this generalized "reconstruction of the crime" was published by numerous workers, including some range survey data collected from the land shown in this photograph. The case against overgrazing and animal disseminatioin of mesquite seed was not clear-cut (and there were certainly other factors including drought), but as was cited in the introduction of this chapter the role of livestock grazing in desertification was implicated by almost every range scientist who published assessments of this range vegetation over the last 80 years. Students were referred to the up-to-now-conclusive study and synopsis by Gibbens et al. (2005).

Dick-Peddie (1993, p. 116, 140) showed Ephedra trifurca as a "diagnostic (climax) member of Desert Grassland". By contrast E. trifurca was not a climax (diagnostic) member of Chihuhuan Desertscrub and E. torreyana was not a diagnostic member of Desert Grassland. Presence of E. trifurca in the shrub-dominated range plant community shown here (taken in conjuction with presence of larger areas of relict black grama) strongly suggested that this range vegetation was once black grama semidesert grassland. E. trifurca served as an indicator species, a useful concept and application that goes back in the literature at least as far as the monographic Plant Indicators (Clements, 1920)..

45. Branches, leaves, and seeds of longleaf joint-fir or Mormon tea- Size-and-scale along with details of bark and leaf arrangement of E. trifurca were presented in these photographs. E. trifurca can usually be readily distinguished from E. torreyana, with which it often grows, by the branching pattern. Branches of E. trifurca are either solitary or arranged in whorles at shoot nodes (readily seen in the first of these two photographs) whereas branches of E. torreyana are usually arranged in groups of three (Vines, 1960, ps. 39-40) Ephedra leaves are typically reduced to scales. "Longleaf" refers to branches and not the actual scalelike leaves.

Shoots of Ephedra species are browsed only infrequently, mostly under severe overuse/overgrazing when used by cattle and under more varied conditions but with hardly more frequency by the smaller ruminant browsers. The Forest Service summarized that longleaf jointfir was "valuelaes for forage, except, perhaps as an emergency ration" (Forest Service, 1940, BB73). Dayton (1931, p. 13) reported that cattle browsed E. trifurca in winter, but he may have confused this with another Ephedra species as he described E. trifurca as "a rather small bush 2 feet high". The specimen in the preceding photograph and those from which these branches grew were roughly four feet in height.

Ephedra species are dioecious. The two plants that produced the leaders (forester and rangeman term for branches of browse plants) in the two slides shown here were females. Naked seeds surrounded by bracts were present on both plants, but were readily visible only in the second slide.

New Mexico State University College Ranch. Dona Ana County, New Mexico. June, seed-ripe stage.

46. Close-ups of the seed and surrounding structures of longleaf Mormon tea seed- Details of the ovulate (female) cones of Ephedra trifurca. The brownish, parchment-like structures are bracts which surround the naked seed. Ephedra species are gymnosperms (hence proper use of the term cone) and do not bear flowers. Students should not confuse the cone bracts with petals of an angiosperm corolla.

New Mexico State University College Ranch. Dona Ana County, New Mexico. June.

47. Staminate cones on Torrey joint -fir or Mormon tea (Ephedra torreyana)- Pollen (polliniferous) cones on branches of shoots from a male plant of E. torreyana. The pollen-bearing male structures are referred to as "stamens" (hence, staminate cones) or as staminate catkins even though gymnosperms are not flowering plants and therefore do not, strictly speaking, have stamens. (Benson, 1979, p. 608) referred to these male organs as microsporophylls, each of which has five or six sporangia with the whole structure being subtended by paired scales.

Midland County, Texas. April, full-pollen stage..

48. The following series of three photographs represented trhe mixed grass semidesert grassland prairie. This is generally one of the most xeric forms of true or "straight" semidesert grassland (ie. grassland in contrast to savanna--the various forms of ecotone or transition zone between Chihuhuan Desertscrub and semidesert grassland-- or to shrub-steppe). This grassland actually has the physiogonomy of a prairie. Warnock (in Shiflet, 1994) was quoted in the introduction to this chapter as stating that this range vegetation "forms a prairie". The range plant community shown in the next three slides was an example of the Grama-Muhly-Threeawn (Bouteloua-Muhlenbergia-Aristida) association described by Warnock (in Shiflet, 1994). This range vegetation was a bunchgrass prairie or steppe. Even though some of the gramas, especially the regional dominant black grama, are stoloniferous and reproduce primarily by asexual means the sward has an open appearance with substantial bare ground among grass clumps. (This was shown and explained for black grama-dominated grassland range earlier.) Muhlenbergia and Aristida species are almost always strictly cespitose species (bunch grasses that have only tillers, vertical shoots). Thus the clumped physiogonomy of this beautiful prairie.

El Paso County, Texas. June.

49A. Physiogonomy of mixed grass semidesert grassland prairie- Black grama and the cespitose threeawn (wiregrass) and muhly species formed this bunchgrass prairie "smack-dab" in the middle of the Chihuhuan Region. This xeric prairie was "engulfed" in the prevailing Chihuhuan Desertscrub. How much, if any, of this desert vegetation was man-caused disclimax was unknown. One thing was certain: this was virgin (= climax) range vegetation. Even more remarkable was location of this relict vegetation. This pristine range plant community was on the old El Camino Real, the Spanish-Mexican trade route from Santa Fe to Chihuhua City, less than two miles from the Rio Grande.

Dominance was shared fairly equally among Wrights' threeawn (Aristida wrightii), black grama, and bush muhly. Wright's threeawn was the most common (apparent density and cover), but the author did not feel that this was so obvious as to declare Wright's threeawn as the dominant. Besides, there were also substantial numbers of plants and plant cover from red threeawn (Aristida longistea). Plus, so many of the threeawn plants had shed their spikelets that positive identification was impossible. In addition to black grama, hairy grama, annual sixweeks grama, and even a few sideoats grama plants were also present. Bush muhly was the most common Muhlenbergia species, but ring muhly and sand muhly (M. arenicola) were also "present and accounted for" though in small proportions. Presence of the latter two species and sideoats grama was of more ecological importance as indicator species than as major constituent species.Mesa dropseed was a major species and fluffgrass was common enough that these were locally important ingredients in the graminaceous stew.

Very infrequent shrub species included soaptree yucca, creosotebush, and mariola (Parthenium incanum). The most common forb at this season was annual scorpionweed (Phacelia integrifolia). Dried "remains" of tumble mustard (Sisymbrium altissimum) attested to general abundance of this cool-season alien (and weedy) annual forb during winter and spring.

El Paso County, Texas. June; estival aspect for shrubs but dormancy stage for dominant perennial grasses prior to initiation of summer rainy period. FRES No. 40 (Desert Grasslands Ecosystem). No appropriate unit in Kuchler (1964) or Kuchler in Garrison et al. (1977). SRM 713 (Grama-Muhly-Threeawn). No appropritate biotic community in Brown et al. (1998). Chihuhuan Deserts- Chihuhuan Desert Grasslands Ecoregion, 24 b (Griffith et al., 2004).

49B. Prairie in the desert?- Yes, sort of. To be precise it is prairie in the semidesert or grassland-desert transition of Shreve (1917). Prairie is grassland which by definition cannot be desert, but the prevailing vegetation of this region is Chihuhuan Desert and the vegetation surrounding this grassland was desert. This was another example of the patchwork of range plant communities or the vegetational mosaic of this extensive range region.

This was a "picture-perfect" example of the grama-muhly-threeawn bunchgrass prairie form of semidesert grassland. The predominant gramagrass was black grama. Hairy grama and sideoats grama were present though scarce, especially when compared to black grama. Bush muhly was the major Muhlenbergia species, but sand muhly and even sand muhly were also in this grass community. The most common grass in this photograph was Wright's threeawn, but red threeawn was also common and after seed-shatter in some individuals it was not possible to distinguish among Aristida species. Mesa dropseed was distributed more-or-less uniformly throughout this range plant community. The predominant shrub in the background was soaptree yucca.

Area not occupied by plants (= "bare soil") was conspicuous and of considerable size relative to area covered by plants.This is characteristic of grasslands composed of cespitose grass species (bunchgrasses).

El Paso County, Texas. June, but still primarily the dormant season for perennial grasses before onset of summer rains. FRES No. 40 (Desert Grasslands Ecosystem). No appropriate unit in Kuchler (1964) or Kuchler in Garrison et al. (1977).for this range type.SRM 713 (Grama-Muhly-Threeawn). No appropriate Brown et al. (1998) biotic community. Chihuhuan Deserts- Chihuhuah Desert Grasslands Ecoregion, 24b (Griffith et al. 2005).

49C. Interior appearance of a grama-muhly-threeawn semidesert prairie- This inside view of an example of the Bouteloua-Muhlenbergia-Aristida association was a composite of the species make-up and botanical structure of this rangeland cover type. Species visible included Wright's threeawn, mesa dropseed, black grama, and bush muhly. The latter two species were represented by small (and presumedly younger) individuals. The shrub in the left rear corner of the photograph was mariola.

El Paso County, Texas. June; still dormancy for dominant perennial grasses before beginning of summer rains. FRES No. 40 (Desert Grasslands Ecosytem). No appropriate Kuchler (1964, in Garrison et al., 1977) unit. SRM 713 (Grama-Muhly-Threeawn). No appropriate Brown et al (1998) biotic community. Chihuhuan Deserts- Chihuhuan Desert Grasslands Ecoregion, 24 b (Griffith et al., 2004).

50. Wright's threeawn (Aristida wrightii)- This bunchgrass was one of the dominants in the Grama-Muhly-Threeawn cover type (SRM 713). Wright's threeawn was also an indicator species that helped distinguish this from other rangeland cover types in the semidesert grassland.

The second slide presented the inflorescence of Wright's threeawn. Basis of "threeawn" was conspicuous.

El Paso County, Texas. June, dormancy stage, just prior to initiation of current growing season (immediately before "green-up").

51. Sand dunes and related small land forms like hummocks appear frequently but sporatically throughout portions of the general Chihuhuan and Sonoran Desert Regions, including some of the semidesert grasslands and related range vegetation. The following three photographs were used as a series to represent the sand dunes savannah form of semidesert grassland. This range vegetation has not been described-- at least not with any regularity-- in major works devoted to semidesert grassland or related vegetation. For example, it was not noted in The Desert Grassland (McClaran and Van Devender, 1995) and it was represented by the more general form of sand dune shrubland by Warnock(1974, Fig, 23).

This is one of the more restricted and smaller spatial (acreage-wise) kinds of semidesert grassland. Floristic composition and structure is unique (and, as students will soon see, picturesque).

51A. Sand dune savanna- Exterior view showing physiogonomy, structure and botanical composition of of a deep sand, semi-stabilized dunes supporting a savanna of shrubs and dune-adapted perennial grasses. Dominant grasses were giant dropseed (Sporobolus gigantea) and mesa dropseed with spike dropseed (S. contractus) an associate herbaceous species. Shrubs included sand sagebrush (Artemisia filifolia) and broom dalea or broom pea (Dalea scoparia), both of which were local woody dominants (and appeared as gray, symmetrically rounded bushes in this photograph). Associated shrubs included longleaf jointfir and a few individuals of plains yccca (Yucca campestris). The co-dominant herbaceous species were giant dropseed (Sporobolus gigantea) and mesa dropseed. Apparent dominance of shrubs was an example of aspect dominance more than of actual dominance based on proportion of plant cover.

The most conspicuous perennial forb was leatherweed or leather-weed croton (Croton pottsii). Annual forb species consisted of Texas croton (C. texensis), trumpet-, paleflower- or whiteflower gilia (Gilia longiflora= Ipomopsis longiflora), scorpionweed, and tumble mustard.

Dominance based on role and control (domination) of the range plant community was not known, but it seemed apparent based on percentage cover (basal or foliar) and "guestimated" annual production of plant material (biomass was not measrued) that dropseed species were the plant community dominants. This was a savanna, but more of the form of a shrub steppe and not a desertscrub-grassland ecotone. The author interpreted this range vegetation as climax or, at least, a seral stage that approached climax. Giant dropseed was seen as an indictor species and keystone species the dominance by which was strong evidence for a range plant community that was close to potential natural vegetation.

Hudspeth County, Texas. June, early growth of perennial herbs (just before onset of summer rainy period). FRES No. 40 (Deert Grasslands Ecosystem). No specific units from Kuchler (1964, in Garrison et al., 1977), Brown et al., (1998), ofr Society for Range Management (Shiflet, 1994). Chihuhuan Deserts- Chihuhuan Desert Grasslands Ecoregion, 24b (Griffith et al., 2004). Sand Hills range site, Desert Grassland vegetation zone (Soil Conservation Service descriptions).

51B. Species composition of sand dune savanna semidesert grassland- "Sample" of range vegetation on the relatively restricted deep sand or sand dune savanna form of "desert grassland". In the foreground giant and mesa dropseed were clearly visible. An extra large giant dropseed was to left-rear of the largest plant (the silvery gray shrub), a specimen of broom dalea or broom pea. Several sand sagebrush plants were in right background. Plains yucca and longleaf joint-fir were also present in smaller proportions based on both foliar and plant density. Annual forbs included scorpionweed and trumpet gilia. Leather-weed croton was the obvious perennial forb.

Hudspeth County, Texas. June, still early in warm-season growing period as prior to most of summer rains.FRES No. 40 (Desert Grasslands Ecosystem). No appropriate units from Kuchler (1964, in Garrison et al., 1977), Brown et al. (1998), or Society for Range Management (Shiflet, 1994). Chihuhuan Deserts-Chihuhuan Desert Grasslands Ecoregion, 24b (Griffith et al., 2004). Sand Hills range site, Desert Grassland vegetation zone (Soil Conservation Service published description).

51C. Sand dune savanna semidesert grassland- Inside a sand dune range community dominated by giant dropseed and mesa dropseed and with sand sagebrush and broom dalea as associate species. The two large grass plants with both previous season dead herbage and current growing shoots were goiant dropseed. The smaller grasses in the foreground were mesa dropseed and spike dropseed. The largest shrub was broom pea or broom dalea. Background shrubs were mostly sand sagebrush.Also in background were some smaller plants of plains yucca Broom dalea and sand sagebrush could be interpreted as dominants such that perennial grasses and shrubs were co-dominant. More than likely, however, Sporobolus species exceeded woody plants by standards of peak standing crop (or primary productivity), cover, and density.

Students must remember that woody plants like the shrubs shown here have aboveground perennial parts so as to be larger (at least, appear larger) most of the year than herbaceous plants which die back to the ground at end of each growing season. In this photograph giant dropseed plants consisted of sprawling, sparse, dead shoots produced the previous growing season plus new growth (visible as green shoots) produced in early part of the current growing season. Yet giant dropseed--at time of photograph-- appeared smaller than plants of sand sagebrush and broom dalea which had many years (growing seasons) of accumulated growth. It current growing season biomass (live plant weight produced in any one year) of grasses and shrubs was measured and compared at peak standing crop (point or stage of maximum biomass) it would probably be found that giant dropseed produced more plant tissue and underwent greater total photosynthesis than shrubs (ie, giant dropseed would have greater gross primary productivity and/or net primary productivity). This might be true for the smaller mesa and spike dropseed as well. If, as seemed likely, grasses individually or collectively produced greater mass of plant material in a single year, it could be assumed that Sporobolus species were dominant over shrub species even though the plants of shrub species had greater cover and plant mass that had been accumulated over many growing seasons. Furthermore, most of the total (accumulated and current; the sum of) organic matter (measured or estimated as mass) of woody plants was dead. Such dead accumulated plant material is necromass and not biomass (weight of living plant tissue).

Role or impact of plant cover and plant material as well as primary productivity must be accumulated in determining or deciding upon dominance. It is possible, for instance, that shrub tissue (necromass and biomass) stored so much of available soil nutrients or cast enough shad edue to greater cover that shrubs like sand sagebrush or broom dalea had a controlling influence on the more procductive grasses. Alternatively, it is possible that the turnover of herbaceous grass organic matter--including that of roots and shoots-- controlled nutrient cycling to the extent that grasses dominated shrub growth and productivity. Or, maybe, the shallower roots of grasses absorbed soil water (precipitation) more effeciently or effectively than the shrubs. Maybe, shrubs had the advantage in regards soil water aand its use due to deeper, more expansive root systems.

Short forbs in center were leather-weed croton. The small white composite in center midground was plains blackfoot (Melampodium leucanthum). Scorpionweed was also present as at left corner of photograph.

Hudspeth County, Texas. June, still early in spring-summer growing season for perennials. FRES No. 40 (Desert Grasslands Ecosystem). No appropriate units of Kuchler (1964), Brown et al. (1998), or Society for Range Management (Shiflet, 1994). Chihuhuan Deserts- Chihuhuan Desert Grasslands Ecoregion, 24b (Griffith et al., 2004). Sand H:ills range site, Desert Grassland vegetation zone (Soil Conservation Service published description).

56. Another form of Trans-Pecos semidesert grassland- Unique grassland community at extreme eastern edge of the Trans Pecos Basin and Range Vegetation Area of Texas. One of the most xeric forms of mixed grass (mid and shortgrass species) steppe had developed along the westernmost margins of Great plains mixed prairie and beginning of the Semidesert Zone. This transition grassland had more features of the semidesert grassland than High Plains mixed prairie fbased on criteria of plant species composition, physiogonomy, and biomass production. This was an example of a gypseous (gypsum-containing) soil variant of semidesert grassland.

The dominant species was bush muhly with associate species varying from tobosagrass, gyp(sum) grama (Bouteloua breviseta), and/or cane bluestem (Andropogon barbinodis). Other locally important climax grasses included Hall's panicgrass (Panicum hallii), alkali sacaton, and sideoats grama. The most common herbaceous invaders were burrograss (Scleropogon brevifolius), fluffgrass, and sixweek's grama (Bouteloua barbata). Red threeawn (Aristida longiseta) and Wright's threeawn (A. wrightii) were well-represented. Successional status of these perennial Aristida species was not known, butthey were most likely increasers in this range type and on this range site.

.Tarbush and creosotebush were the co-dominant shrub species though tarbush was more abundant with greater density, cover, and consistency. These two shrubs were unquestionably members of the climax plant community, perhaps so much as to create a natural savanna or savanna-like grassland. .Tarbush and creosotebush had increased due to overgrazing, oil development, cessation of fire, and perhaps such natural disturbances as great climatic fluctuations two-thirds to three-fourths of a century prior to this time. A chemical brush control using tebuthiron, N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-z-yl]-N,N-dimethylurea, had killed most of these woody co-dominants on this range, but remaining cover probably resembled that of the pre-white man vegetation. Jimmyweed (Haplopappus heterophyllus) was another shrub on this semidesert grassland range, but this compositae (of the aster tribe, Astereae) was not common. Nor was broom snakeweed which was also present only on occasional spots and then not abundant.

Part of this range seemed to be as much, if not more, of a transition between semidesert grassland and Chihuhuan Desert than of mixed prairie and semidesert grassland (see below).. This may have been due to greater degree of range retrogression and brush invasion over that portion of the range. This pasture was all the same range site.

The second of these two slides was a closer-i9n view of the left foreground of the first slide. Cane bluestem was conspicuous in both of these photographs.

Railway Ranch, Upton County, Texas. Mid-October; peak standing crop and grain-ripe stage of major grasses. FRES No.40 (Desert Grasslands Ecosystem). K-48 (Grama-Tobosa Prairie). SRM 505 (Grama-Tobosa Shrub). Mixed Grass-Scrub Series 143.124 of Chihuhuan (Semidesert) Grassland biotic community 143.1 of Brown et al. (1998, p.40). Gyp range site. High Plains- Arid Llano Estacado, 25k (Griffith et al., 2004).

57. Ecotonal semidesert grassland- Semidesert grassland dominated by bush muhly with tobosagrass, cane bluestem, and gyp grama local associates. Other grasses included Hall's panicgrass, alkali sacaton, and sideoats grama as other decreasers or increasers; red and Wright's threeawns that were probably increasers; and burrograss, fluffgrass, and sixweeks grama, all invaders. Tarbush and creosotebush were co-dominant shrubs though tarbush was first of these two. Jimmyweed and broom snakeweed were incidental shrubs or subshrubs.

This was a portion of the same range as that presented immediately above. There were more live plants of tarbush and creosotebush than on other parts of this particular pasture. This range had been treated with tebuthiron, a substituted urea herbicide, to kill woody plants and it was not known if the portion featured in the foreground of this slide had been treated or treated as effectively as portions with more dead plants of these two shrubs. Alternatively, some dead tarbush and creosotebush plants appeared to have killed due to competition from bush muhly. This is a widespread phenomenon throughout much of the Trans Pecos Region when reduced grazing pressure and other factors permit establishment of bush muhly beneath or, at least, in close proximity to these two dominant shrubs. Two examples of this shrub-killing competition were shown below.

Irrespective of explanation, greater cover and density of tarbush and creosotebush in conjuction with relatively high foliar cover and density of native grasses created a semidesert grassland savanna or a savanna-like semidesert grassland that was a transition--an ecotone--between the climaxes of semidesert grassland and Chihuhuan Desert. It was self-evident (or nearly so) that the Chihuhuan Desert had advanced eastward and expanded into rangeland that had previously been the so-caled desert grassland. This was an example of desertification, the cause(s) of which were unknown. Overgrazing, oil field activity, and elimination of fire (not in any particular order) were all obvious contributing factors, but it is possible that a unique combination of unusually cold and dry weather approximately 70 years earlier could have set into motion the processes of range retrogression. Therefore, desert advancement could have been partly or even largely natural. Alternatively, it could have been largely anthropogenic so that more desert-like vegetation, including the savanna aspect, was a disturbance climax.

Railway Ranch, Upton County, Texas. Mid-October; peak standing crop and grain-ripe stage of major grasses. FRES No.40 (Desert Grasslands Ecosystem). K-48 (Grama-Tobosa Prairie). SRM 505 (Grama-Tobosa Shrub). Mixed Grass-Scrub Series 143.124 of Chihuhuan (Semidesert) Grassland biotic community 143.1 of Brown et al. (1998, p.40). Gyp range site. High Plains- Arid Llano Estacado, 25k (Griffith et al., 2004).

58. Waging war on desert invaders- Tarbush and creosotebush, Chihuhuan Desert co-dominant invaders on a transition semidesert grassland, were attacked by man using tebuthiron and plants via intense competition. Creosotebush (center foreground) flanked on left and right by a single plant of tarbush. This range had been depleted through a number of contributing factors including cessation of fire, oil field activity, overgrazing (order of importance not known) and, perhaps, aberrant atmospheric conditions roughly 70 years earlier. Vegetational results of this range deterioration were increase in cover of native shrubs (primarily tarbush and creosotebush) and decline in abundance (density, cover, distribution or frequency) of decreaser and increaser species of grasses. Range managers resorted to improved grazing management and chemical brush control in attempts to reverse the trend in species composition and structure of the range vegetation. The result was an outstanding kill (apparent root kill at that) of brush (mostly tarbush followed closely by declines of creosotebush) and commensurate increase in grass abundance. This was most apparent for bush muhly followed by increased cover and density of tobosagrass, cane bluestem, and alkali sacaton as other major decreasers along with greater abundance of gyp grama and Hall's panicgrass.

Given that some grazing (of improved management practices) by cattle took place on this range it could not be determined the relative degree to which death of brush and increased abundance of grass was due to herbicidal treatment versus improved grazing management. It is common knowledge among rangemen working throughout this area of the Trans Pecos Basin and Range that when bush muly can establish beside, beneath, etc. adult plants of tarbush and creosotebush this grass commonly kills the shrub. Among numerous management practices that permit establishment of bush muhly is better grazing management such as reduced stocking rate, change in season of use, and deferment of grazing. It is commonly assumed that flourishing of bush muhly and death of shrubs is a result (partial result) of competition, for whatever resource is unknown.

It will be observed that shrubs in the restricted area shown in foreground of this photograph had not been treated with tebuthiron, at least not effectively as in the background where most tarbush and creosotebush had been killed. This area appeared to be outside the rangeland that had received chemical treatment. Observant observers will note that relatively small plants of bush muhly were growing beside adult tarbush and creosotebush. Would these bush muhly plants have been larger and more robust if the shrubs had been killed by tebuthiron? Or had bush muhly established due to improved grazing practices and subsequently the shrubs were slowly dying from intense competition? God, not us, knows. And we will never know without carefully designed experiments.

Railway Ranch, Upton County, Texas. Mid-October; peak standing crop and grain-ripe stage of major grasses. FRES No.40 (Desert Grasslands Ecosystem). K-48 (Grama-Tobosa Prairie). SRM 505 (Grama-Tobosa Shrub). Mixed Grass-Scrub Series 143.124 of Chihuhuan (Semidesert) Grassland biotic community 143.1 of Brown et al. (1998, p.40). Gyp range site. High Plains- Arid Llano Estacado, 25k (Griffith et al., 2004).

59. Grass victorious- A degraded semidesert grassland cattle range composed of bush muhly (the dominant), tobosagrass, cane bluestem, alkali sacaton, gyp grama, Hall's panicgrass, sideoats grama, red threeawn, and Wright's threeawn with successionally excessive abundance of tarbush and creosotebush, co-dominant shrubs, had been treated with tebuthiron a number of years prior to these photographs. A rough visual estimate was that fully three-fourths (probably more) of the two major shrubs had been killed and a commensurate increase in grass cover, biomass, density, etc. had occurred. Obviously this was a phenomenal transformation in the range vegetation, the extent of range improvement as estimated by the increase in range condition class. No wonder this range demonstration was used as a case history that became a highly successful promotional example of the effectiveness of tebuthiron. A well-earned tip of the hat.

A salute rendered, it must be noted that scientifically it cannot be concluded that such improvement is due--either in part or wholly--to the herbicide treatment. The trial was confounded because this tebuthiron-treated range was also grazed by cattle under better grazing management during the herbicide experiment. Was the obvious, undeniable improvement in range condition (an outcome of secondary plant succession) due to application of tebuthiron or to better grazing management or some combination thereof (or to neither one and instead other though unknown variables). This situation is always the case when a problem is subjected to a number of joint treatments without separate treatment applications and, hence, the capability to partition out effects and affects. It is well-known by rangemen in the Trans Pecos Basin and Range Region that establishment of bush muhly in close proximity to shrubs like tarbush and creosotebush commonly results in death of the woody plants. This takes place in absence of brush control treatments. Judicious grazing appears to permit more establishment of bush muhly. Neither can it be ruled out, however, that shrubs act as nurse plants for bush muhly (ultimately resulting in shrub death). Range scientists simply do not know.

The immense plant of bush muhly in the second of these slides (and the edge of another bush muhly in far left margin) were growing around what remained of dead tarbush plants that could (might) have been killed as results from competiton with bush muhly. These plants were outside of the tebuthiron-treated range that was shown in the first of these photographs, but it was also possible that some "stray" (undirected) tebuthiron had killed the tarbush plants thereby permitting establishment and monumental growth of the "champion" bush muhlys. Again, only God knows-- from this trial anyway.

Railway Ranch, Upton County, Texas. Mid-October; peak standing crop and grain-ripe stage of major grasses. FRES No.40 (Desert Grasslands Ecosystem). K-48 (Grama-Tobosa Prairie). SRM 505 (Grama-Tobosa Shrub). Mixed Grass-Scrub Series 143.124 of Chihuhuan (Semidesert) Grassland biotic community 143.1 of Brown et al. (1998, p.40). Gyp range site. High Plains- Arid Llano Estacado, 25k (Griffith et al., 2004).

60. Sample of semidesert assembly- Gyp grama, cane bluestem, and burrograss growing in close association in the sward of a transition semidesert grassland situated between an island of Chihuhuan Desert scrub and xeric mixed prairie at eastern margin of the Trans Pecos Basin and Range Region of west Texas. Along the border of the southern and drier Southern High Plains (Llano Estacado or Staked Plains) and the eastern outliers area of the Basin and Range physiographic province there is a mosaic (patchwork pattern) of mixed prairie grassland, semidesert grassland, and Chihuhuan Desert (a shrubland type). Any number of factors can result in conversion of one or two of these range types into one or two of the other types.

The "photoplot" seen here was on the depleted and now recovering--through range improvement practices--semidesert grassland that had been used as a cattle range and oil field for decades. Usually, it can comed back.

Railway Ranch, Upton County, Texas. Mid-October; peak standing crop and grain-ripe stage of major grasses. FRES No.40 (Desert Grasslands Ecosystem). K-48 (Grama-Tobosa Prairie). SRM 505 (Grama-Tobosa Shrub). Mixed Grass-Scrub Series 143.124 of Chihuhuan (Semidesert) Grassland biotic community 143.1 of Brown et al. (1998, p.40). Gyp range site. High Plains- Arid Llano Estacado, 25k (Griffith et al., 2004).

61. Mixed grass (grama-bluestem-cottontop) hillside grassland- Represented here was another of the less widespread kinds or forms of semidesert grassland. This range type was described in the introduction to this chapter and was not be repeated here. In the example above sideoats grama and cane bluestem were co-dominant grasses. Dominance by these two decreaser mid-grass species was the defining feature of this range cover type. Other major grasses included black and chino grama, plains bristlegrass, and perennial threeawns (mostly red threeawn). Arizona cottontop, tanglehead, and bush muhly were present in much smaller amounts. Fluffgrass was also present in smaller proportions. Forbs were extremely rare, even composites, and irrelevant. Important shrubs included mariola, skeletonleaf goldeneye, whitethorn acacia, sacahuista, tasillo(Opuntia leptocaulis), and Engelmann's pricklypear (O. engelmannii var. engelmannii).

This semidesert grassland range type is typically more varied that some of the more widely occurring types (probably including the black grama semidesert grassland type, most common of all). This is undoubtedly attributable to gret diversity of habitat factors associated with hills and mountains including slope and aspect, soils and parent materials, and numerous atmospheric variables that go along with slope, aspect, and elevation.

Chinati Mountains, Presidio County, Texas. June, early estival aspect prior to typical summer rainy period. FRES No. 40 (Desert Grasslands Ecosystem). No appropriate units in Kuchler (1964, in Garrison et al.., 1977), Brown et al. (1998), or Society for Range Management (Shiflet, 1994). The Bouteloua-Andropogon-Trichachne post-climax (sideoats grama-feather grass- Arizona cotton grass) type of Whitfield and Brutner (1938). This semidesert grassland range type should be described by the Society for Range Management as Grama-Bluestem-Arizona Cottontop Shrub rangeland cover type if and when there is a second version of Rangeland Cover Types . Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004). Igneous Hill and Mountain range site, Desert Grassland vegetation zone (Soil Conservation Service, Soil Survey of Jeff Davis County, Texas).

62. Cane bluestem (Andropogon barbinodis= Bothriochloa barbinodis var. barbinodis)- This widely distributed mid-grass is a climax dominant (decreaser) on more mesic range sites of semidesert grasslands and Chihuhuan Desert The discontinuous biological range of this species extends from Uruguay and Argentina in South America northward to Colorado and California (Gould, 1975, p. 600).

Railway Ranch, Upton County, Texas. Mid-October; grain-ripe stage and peak standing crop.

63. Chino grama-Chihuhuan Desert shrub savanna- The Chihuhuan Desert and semidesert (Chihuhuan) grassland communities form a vegetational mosaic with each other across much of the greater Chihuhuan Region. Countless local ecotones (localized transition zones) are thus part of the "patchwork" of range plant communities across this diverse landscape that itself was seen as a Desert-Grassland Transition by Shreve (1917). There are thus smaller ectones within a larger general ecotone, all of which could be climax vegetation. Some such transition zones are range plant communities doubtless existing in some stage of retrogression as semidesert grassland has been (or is being) degraded under human influence to disclimax Chihuhuan Desertscrub.

The range vegetation shown here was a rather obvious (at least to this author-photographer) example of climax ecotonal Chihuhuan Desert-semidesert grassland transition. The vegetation of the particular range that included the "sample" shown here extended from creosotebush plains desert in a basin to chino grama foothill grassland higher up on the foothills of north and east slopes. The range plant community that developed on this southwest-facing hillside was a "mixture" of basin Chihuhuan Desert dominated by creosotebush and ocotillo and foothill chino grama grassland. Range vegetation on this xeric "transect" that extended from bajada (bench) to rimrock of a hilltop was a "textbook exampl"e of the savanna that develops where desert and grassland of the Chihuhuan Region meet and mingle. Based on early descriptions of natural or climax vegetation by ecologists like Shreve (1917, 1942), Clements (1920), Shantz and Zon (1924) and summaries by later ecologist like Dick-Peddie (1993) this savanna was climax vegetation characteristic of one of the major general natural plant communities of the virgin (= pre-Columbian) range. This is an example of a relict or relict vegetation that can be used as a range reference area. In fact, this sample of range vegetation could probably serve as a research natural area (Laycock, 1975 generally and especially, p. 11). Relict was defined by the Society for Range Management as: "A remnant or fragment of the climax plant community that remains from a former period when it was more widely distributed. Syn. pristine" (Jacoby, 1989).

On this savanna the dominant range plant was chino grama which made up most of the herbaceous understorey. Black grama and red threeawn were associate grass species; bush muhly and cane bluestem were "also-ran" but indicator species. Dominant shrubs were creosotebush, the regional dominant of both Chihuhuan and Sonoran Deserts, and ocotillo. Other shrubs present included the euphorbia leatherstem or sangre de drago, dragon's blood, (Jatropha dioica), whitethorn acacia and, of course, honey mesquite. The very low cover of mesquite, especially in conjuction with abundance of decreaser grass species was an indication as to the pristine condition of the range vegetation on this photographic transect.

63A. Chino grama-Chihuhuan Desert shrub savanna- Transect-like view of a hillside ecotone between basin creosotebush plains desert and chino grama foothill grassland. Chino grama was the dominant of this plant community which indicated the identification of this range cover type as grassland and not shrubland (desert). Black grama and, rarely, sideoats grama, cane bluestem, red threeawn, and bush muhly were locally common. This combination of grass species demonstrated the floristic relationship of this rangeland cover type with the mixed grass (Grama-Bluestem-Arizona Cottontop-Shrub) cover type presented immediately above.

Ocotillo was conspicuous being "fully clothed" with ephemeral, drought-deciduous leaves, but perennial grasses had just begun new growth prior to onset of summer rains (hopefully). Creosotebush was dominant shrub on this savanna. Creosotebush is the zonal dominant of the Chihuhuan and Sonoran Deserts as well as much of the Mojave Desert, Presence of creosotebush as a dominant in this climax vegetation indicated the affinity of desertscrub and grassland biomes under proximite (usually adjacent) location to each other throughout this region. Forbs were so rare as to be irrelevant.

The igneous parent material of this soil was obvious on the land surface.

Bofecillos Mountains, Big Bend Ranch State Park, Presidio County, Texas. June, early estival aspect at start of "green-up" of perennial grasses. FRES No. 40. No appropriate units for vegetation in Kuchler (1964, in Garrison, 1977), Society for Range Management (Shiflet, 1994), or Brown et al., (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).

63B. Transition Chihuhuan Desert-Grassland Savanna- "Overlap" of chino grama-dominated foothill semidesert grassland and plains creosotebush Chihuhuan Desert resulted in development of this chino grama-creosotebush savanna. This range vegetation could be handily described as a Chihuhuan shrub-steppe. The range plant community is a "synopsis shot" of what ecologists from Shreve (1917) to Dick-Peddie (1993, ps.106-107) described variously as "Desert-Grassland Transition", "desert savanna", "desert shrub grassland", "shrub steppe", and "grassland transition". "The transitional nature of this vegetation is apparent from these names" (Dick-Peddie, 1993, p. 106).

Prevalence of the cespitose chino grama (most of the buckskin-colored clumps) was obvious in both of these slides. The large (probably very old) chino grama highlighted or backgrounded by the large igneous rock in left foreground was a good example of the habit of this species as it appears on the range. In addition to conspicuous individuals of the dominant shrubs, creosotebush and ocotillo, specimens of leatherstem were also obvious (in foreground and near midground of both slides and midground at far right margin of slide on the right). Taller shoots of cane bluestem, a mid-grass associate species, were visible in foreground of slide on the right. Sideoats and black grama were locally abundant, but nowhere did they approach the abundance of chino grama. Red threeawn and bush muhly were also common, especially at edges of larger bare areas and close to shrubs, respectively.

Physiography of the Basin and Range physiographic province and igneous parent material of soils was apparent in these two photographs as well as ind the preceding photograph.

Bofecillos Mountains, Big Bend Ranch State Park, Presidio County, Texas. June, early estival aspect with growth of shrubs being more advanced than that of perennial grasses which were still in early stages of "green-up" (iniital annual growth).FRES No. 40. No apt units for vegetation in Kuchler (1964, in Garrison et al., 1977), Society for Range Management (Shiflet, 1994), or Brown et al., (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).

63C. Detail of range vegetation in ecotone of Chihuhuan Desert shrub-foothill chino grama grassland- This range plant community was a savanna-- transition zone-- between the Chihuhuan Desert creosotebush plains (in a lower basin) and the "straight" or "pure" chino grama-dominated grassland of bajadas (benches) and slopes that were immediatly above (adjacent to) the basin. Chino gram was dominant. Black and sideoats grama were also present. All perennial grasses were still in dormancy to early growth stages as time of photograph was before beginning of summer rain.period. There were no annual grasses. Dead stems of winter annual forbs (foreground) were mostly of tumble mustard.

Desert pavement of land surface was visible.

Bofecillos Mountains, Big Bend Ranch State Park, Presidio County, Texas. June, early estival aspect at early stages of new growth in perennial grasses. FRES No. 40 (Desert Grassland Ecosystem). No appropriate units for vegetation in Kuchler (1964, in Garrison, 1977), Society for Range Management (Shiflet, 1994), or Brown et al., (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).

64. Sotol-lechiguilla-grama grassland- The following series of five photographs presented one of the larger and better known kinds or forms of semidesert grassland known by such designations as the sotol grasslands (Wauer, 1980, ps.20, 22-23) or the lechuguilla-chino grama association (Warnock, 1974, p 47.). The current author included both liliaceous shrubs in his title based on previous designations like those just cited as well as his observations that sotol and lechuguilla are usually both present on this range cover type. It was remarked in the introduction of this chapter that it was somewhat odd that the Society for Range Management (Shiflet, 1994) did not provide a title and description for this rangeland cover type given that the same had already appeared in publications, including by the National Park Service and Warnock (1974) the latter of whom did provide the title and description for one of the semidesert grassland rangeland cover types in Shiflet (1994). Regardless, the distinctive and readily discerned sotol-lechuguilla-grama (usually chino grama) grassland was treated here and now.

Readers can also discern that this climax range vegetation is a savannah or, at least, is savannah-like in appearance. It could be described as a savannah. The published accounts of this range plant community generally entitled it "grassland" and not "savanna". This author followed the precidence set by these published descriptions and identified this potential natural (= climax) vegetation as grassland noting the aspect dominance quality provided by sotol and lechuguilla. It was explained above for the sand dune savanna semidesert grassland that woody plants with aboveground perennating parts are typically larger and often occupy considerably greater proportions of total plant cover than herbaceous plants, but this increase took place over a number of growing seasons (perhaps decades). This growth pattern and resultant plant habit must be taken into account when making comparisons of woody plants with herbaceous species that have no aboveground perennating portions and thus do not accumulate aboveground plant material on par (that can be compared) with shrubs and trees.

The sotol-lechuguilla-gramagrass range type is generally found as the highest elevation grassland in areas where it develops. This form of semidesert grassland is largely determined by elevation and related habitat factors including slope and soil features. In mountains as, for example the Chisos Range, sotol-lechuguilla-gramagrass occurs as elevational zone vegetation adjacent to (elevationally just below) the oak-pinyon pine-juniper woodland and immediately above the chino grama foothill grassland zone. On some hills and lower mountains (and depending on topographic, edaphic, and other factors) the sotol-lechuguilla gramagrass cover type is the uppermost zone of range vegetation. Examples of sotol-lechuguilla-gramagrass grassland on both of these elevation-determined environments were presented below.

64A. Sotol-gramagrass grassland- Lechuguilla was absent from this savanna-like, hill-occupying grassland. The dominant herbaceous range plant was sideoats grama, followed by chino and black grama, cane bluestem, threeawn species (mostly of the Aristida purpurea complex, especially A. purpurea var. longiseta= A. longiseta), buffalograss, fluffgrass, plains bristlegrass, and hairy tridens (Tridens pilosus= Erioneuron pilosum) such that there was a full-array of decreasers, increasers, and invaders from the Gramineae. Forbs were extremely limited (mostly composites). Common shrubs on this range besides the dominant sotol were tasajillo, cane cholla (Opuntia imbricata), and pricklypear (mostly Englemann's pricklypear) cactus and broom snakeweed. Spanish dagger or Torrey yucca (Yucca torreyi= Y. treculena= Y. macrocarpa) was present as isolated speciments. Mesquite and Acacia species plus sacahuista were conspicuous by their absence (for all practical purposes).

This range vegetation had developed on high rolling hills (not mountains) and occupied entire hill slopes from above valley or basin with creosotebush plains form of Chihuhuan Desert to tops of hills like the one on which this photograph was taken.

This range had just been through the Long Drought of the 1990s-2000s. Obviously it had been stocked accordingly as grass vigor was high and range condition class was or approached Excellent. There were no obvious indications that range trend was downward.

Private property, Chinati Mountains, Presidio County, Texas. June, early estival aspect with almost no new grass growth (ie. prior to "green-up"). FRES No. 40 (Desert Grasslands Ecosystem). No appropriate vegetation units in Kuchler (1964, in Garrison et al., 1977), Society for Range Management (Shiflet, 1994), or Brown et al. (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004). Gravelly Hill range site, Desert Grassland vegetation zone (Soil Conservation Service site description). West slope to hill top.

64B. Sotol-gramagrass grassland- Grandeur of the semidesert grassland was displayed across the rolling hills of the Mountains as sotol and a mixture of climax mid- and shortgrass formed this savanna-like grassland. Sideoats grama was the dominant grass with black and chino grama the major associates. Red threeawn (and probably other perennial threeaws), cane bluestem, plains bristlegrass, buffalograss, hairy tridens, and fluffgrass called these hills their home. Other grasses that were likely present but not detected by the photographer included tanglehead, green sprangletop, and Arizona cottontop. Forbs were essentially absent as were leguminous shrubs including honey mesquite and Acacia species as well as lechuguilla and sacahauista. In addition to sotol other common shrubs were Englemann pricklypear, tasajillo, and cane cholla along with the suffrutescent broom snakeweed. Spanish dagger (also known as Torrey yucca) was present as widely scattered individual plants.

Good example of habit of cespitose grass species (bunchgrasses), and of the pristine expression of this rangeland cover type.

Private property, Chinati Mountains, Presidio County, Texas. June, early estival aspect overall with very little new growth ("green-up") of grasses.FRES No. 40 (Desert Grasslands Ecosystem). No rlelvant unit in Kuchler (1964, in Garrigus et al., 1977), Society for Range Management (Shiflet, 1994), or Brown et al., (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c. Gravelly Hill range site, Desert Grassland vegetation zone (Soil Conservation Service range site description).

64C. Sotol-gramagrass grassland- Physiogonomy, community structure, and species composition of the virgin vegetation of this range cover type of semidesert grassland. Across a seemingly endless range of hills a diverse combination of climax mid- and shortgrass species along with shrubs formed a "textbook example" of the sotol grassland. This pristine range vegetation could be interpreted and described as a sotol-gramagrass savanna, but this author followed the precident of previously published titles and viewed this climax range as grassland with a conspicuous shrub component.

Sideoats grama was the dominant grass with chino and black grama as overall associates. There were patches where other grass species ranging from cane bluestem to fluffgrass to red threeawn dominated. Buffalograss, hairy tridens, and plains bristlegrass were present in small amounts while green sprangletop, Arizona cottontop, and tanglehead were almost assuredly present though not observed by this author.

After sotol the major shrubs were cactus species including pricklypear (mostly Englemann's pricklypear), cane cholla, and tasajillo. Broom snakeweed represented suffrutescent shrubs (and composites in general). Forbs were so sparse as to be irrelevant. Torrey yucca, better known as Spanish dagger, was found only as widely scattered individuals. Lechuguilla, sacahuista, honey mesquite, and Acacia species were noteworthy by their absence from this extraordinary range vegetation.

Private property, Chinati Mountains, Presidio County, Texas. June, early estival aspect with little new growth of grasses (prior to summer rainy period). FRES No. 40 (Desert Grasslands Ecosystem). No pertinent unit of vegetation in Kuchler (1964, in Garrigus et al.l, 1977), Society for Range Management (Shiflet, 1994), or Brown et al., (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004). Gravelly Hill range site, Desert Grassland vegetation zone (Soil Conservation Service range site description).

64D. Sotol-lechuguilla-chino grama grassland- On this range lechuguilla likely outranked sotol in dominance based on both plant cover and density (and likely influence on range plant community and abiotic factors). On this range, chino grama was the dominant grass with black grama and red threeawn associate species. Fluffgrass was most abundant grass species invader. Sideoats grama, cane bluestem, plains bristlegrass, and bush muhly were found but were essentially absent. Also absent were leguminous shrubs (eg. mesquite) as well as creosotebush and ocotillo which were the woody dominants on adjacent lower elevation Chihuhuan Desertscrub.

This was one of several kinds of foothill semidesert grassland. Rough Mountain was at extreme left background, Parent material was pirmarily igneous.

Big Bend National Park, foothills of Chisos Mountains, Brewster County, Texas. June, early estival aspect (before onset of summer rains so very little "green-up" of perennial grasses). No appropriate vegetational unit in Kuchler (1964, in Garrison, 1977), Society for Range Management (Shiflet, 1994), or Brown et al., (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c.

64E. Species-rich sotol-lechuguilla-grama grassland- Tremendous botanical diversity marked this more xeric example of the savanna-like sotol-lechuguilla grama grassland as worthy of inclusion with the preceding pristine and interesting examples of the same range cover type. Where to start? The herbaceous understorey, like the preceding examples, could be viewed as consisting of layers corresponding to height of mature grasses (eg. mid- and shortgrass species). On this drier site red grama was dominant to chino grama and cane bluestem followed by black and sideoats grama (in that order). Shrubs included sotol, lechuguilla, creosotebush, tasajillo, Englemann pricklypear, honey mesquite, cane cholla, mariola, and tarbush. Forbs were quite limited and, like grasses, still in dormancy awaiting summer rains.

Physiography (= topography) of Trans-Pecos Basin and Range was featured prominently in this photograph. Geology of this landscape was volcanic lavas, tuffs, and sedimentary rocks (MacLeod, 2002, p. 26).

Big Bend National Park, Brewster County, Texas. June, early estival aspect (prior to beginning of summer rainy period so very little "green-up" of perennial grasses). No appropriate unit of vegetation in Kuchler (1964, in Garrison, 1977), Society for Range Management (Shiflet, 1994), or Brown et al. (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c.

66. Spanish dagger or Torrey yucca (Yucca treculeana, Y. torreyi= Y. macrocarpa)- Another genus of shrub or, in case of larger individuals, tree on sotol-lechuguilla grama grassland is Yuccca. No Yucca species is a dominant plant on this range cover type to the extent that soaptree yucca is on black grama semidesert grassland. Notwithstanding this situation Yucca species do occur and are locally prominent on sotol-lechuguilla grama grassland range. The more common of these species is Spanish dagger. This species is also a member of the Chihuhuan Desertscrub at lower elevations and oak-pinyon pine-juniper woodland at the higher elevation zone.

Presidio County, Texas. June.

67. Spanish bayonet, giant dagger; or Faxon yucca (Y. carnerosana= Y. faxoniana)- This Yucca species is less common than soaptree and Torrey yucca and it is more likely to grow at higher elevations in foothill and upper mountain slopes in the Trans-Pecos Basin and Range Region.

Classification of Yucca species has remained controversial. Some authors like Smith (1977) treated this genus as the agave subfamily (Agavoideae) of the lily family (Liliaceae) while other taxonomists such as Powell (1988) placed Yucca in the agave family (Agavaceae).

Presidio County, Texas. June.

68. Texas hechtia or Texas false-agave (Hechtia texensis)- One of the most unusual succulents in the Chihuhuan Desert and semidesert grassland vetetation is this member of the pineapple family (Bromeliaceae). This bromeliad is easily confused with the Agave or even Yucca species. While Hechtia is in the Monocotyledoneae it is in a separate family which includes the Spanish moss group.

This was a small group of H. texensis in a community dominated by sotol.

Bofecillos Mountains, Presidio County, Texas. June.

70. Chino grama (= "chinograss") foothill grassland- Chino grama (Bouteloua ramosa) often forms estensive monospecific-- or nearly so-- stands (Clemenentsian consociations) on mountain foothills in the Trans-Pecos Basin and Range Area. Other grass species such as black grama (mostly), sideoats and hairy grama, cane bluestem, threeawn, and bush muhly plus scattered shrubs like creosotebush, cactuses, tarbush, mariola, Acacia species, and ceniza (Leucophyllum species) are often locally important or, more frequently, present as minor components.

This kind or form of semidesert grassland is most prevalent in the mountains of Trans-Pecos Texas. Chinograma grassland primarily occurs as zones in mountain foothills or on higher hills in proximity to Chihuhuan Desertscrub and sotol-lechuguilla-grama grassland. The chinograss zone usually is somewhat "sandwiched" between these other two range plant communities being spatially below and above them, respectively. This rough zonation of Trans-Pecos Basin and Range vegetation (including the oak-pinyon pine-juniper woodland and ponderosa pine forest cover types) is apparently at least a partial function of elevation and effects related to elevation. Obviously soils, slope, directional aspect, and other factors are likely also involved.

Chino grama grassland has affinities with the adjacent zones of vegetation so much so that chino grama is often the dominant, and almost always an associate, herbaceous species in sotol-lechuguilla-grama grassland and Chihunuan Desert-semidesert grassland transition (savanna). The chino grama-dominated foothill grassland can be viewed as the "pure" or "concentrated" expression of grassland dominated by the species in contrast to the transition vegetation (ie. savanna) below and above it elevation-wise.

Chino grama-dominated grassland is considerably more restricted in location and extent (acreage covered) than black grama- and tobosagrass, the major forms (rangeland cover types) of semidesert grassland. Chino grama foothill grassland is also much less striking in physiogonomy (at least to laymen, naturalists, and non-"grassmen type" vegetation scientists) than sotol-lechuguilla-grama grassland. It is maybe for these reasons that this minor --but locally important-- range cover type not treated by those who otherwise described semidesert grassland vegetation. The Society for Range Management (Shiflet, 1994) omitted this range vegetation as a rangeland cover type. Whitfield and Beutner (1938) and Whitfield and Anderson (1938) provided the seminal and still definitive descriptive accounts of "desert plains grassland", and they did not even list Bouteloua ramosa (or a synonym) but did give five Bouteloua species. Neither B. ramosa nor a synonym was included in the classic description of by Clements (1920) in Plant Indicators. Some authorities who described vegetation and grasses of Trans-Pecos Texas did explain importance of chino grama and describe chino grama dominated-semidesert grassland (Maxwell, 1968, ps. 108-109; Warnock, 1974, ps. 26-27; National Park Service, undated, p.84; Powell, 2000, ps. 15, 217-219). None of these publications were devoted to vegetation per se or to its description and classification.

The following series consisting of four slides presented the chino grama foothill grassland range type on par with more widely distributed and better-known cover types of semidesert grassland.

70A. Chino grama semidesert grassland- Landscape scale view of chino grama-dominated foothill grassland in the Trans-Pecos Basin and Range province. Shown here was the physiography and vast expanse of basin and range landform combined with physiogonomy of the range plant community in which the predominately cespitose chino grama is the defining keystone species. Unlike the more common and wider-distributed black grama, chino grama does not have stolons and is strictly a bunchgrass. Physiogonomy and structure of grassland communities dominated by chino grama appears steppe-like with a more open sward than semidesert grassland made up mostly of black grama, tobosa, or mixtures of several species.

Black grama was locally abundant in the range vegetation shown here, but chino grama was the sole dominant. Red threeawn, bush muhly, plains bristlegrass, and fluffgrass were also present but minor species overall. Creosotebush, Englemann pricklypear, lechuguilla, and Big Bend silverleaf (Leucophyllum minus) appeared conspicuously and infrequently.

Big Bend National Park (foothills Burrow Mesa), Brewster County, Texas. June, early estival aspect (prior to beginning of summer rainy period so that grasses were still in state formancy). FRES No. 40 (Desert Grasslands Ecosystem). No appropriate units in Kuchler (1964, in Garrison, 1977), Society for Range Managemeant (Shiflet, 1994), or Brown et al. (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c.

70B. Chino grama-dominated grassland- This low hillside was spatially above a range plant community of Chihuhuan Desertscrub dominated by creosotebush and ocotillo. These two shrub species along with lechuguilla and isolated Englemann pricklypear were minor species to chino grama which was obviously in "complete control" of this foothill rangeland. Large size of individual chino grama plants suggest relatively old age and high plant vigor.

The rimrock atop the hill indicated that this land had been formed under volcanic activity.

70C. Botanical diversity on chino grama foothill semidesert grassland- An array of species, life or growth forms, and groups of range plants were present on Chihuhuan Region grassland that was dominated and defined by chino grama. Was this pristine, or was it pristine? Diverse species composition and structure were striking in this relict range vegetation dominated by chino grama.

Large, orange or yellowish-brown grass clumps in center foreground were cane bluestem. Large specimens of bush muhly were to the sides and behind cane bluestem. Black and sideoats grama and red threeawn were also major, well-represented grass species. The more common shrubs included Spanish dagger (Yucca treculeana= Y. macrocarpa), Englemann's pricklypear, cane cholla along with Acacia and Mimosa species. Sotol and lechuguilla were present but rare. Notice that this rarity contrasted with sotol-lechuguilla grasslands. Forbs were "few and far between" (essentially of no obvious importance).

This range dominance type clearly had a floristic affinity with both the mixed grass (grama-bluestem-Arizona cottontop) hillside graasland and the Chihuhuan Desert-chino grama savanna. Dominance by chino grama (versus sideoats grama) and the relatively smaller proportions of plant cover by other species distinguished this grassland cover type. This was consistent with published descriptions by local authorities and observers as cited in the aabove introduction.

Big Bend National Park(foothills, Burro Mesa), Brewster County, Texas. June, early estival aspect and prior to initiation of grass "green-up" in the current growing season. FRES No. 40 (Desert Grasslands Ecosystem). No apt units of vegetation in Kuchler (1964, in Garrison, 1977), Society for Range Management (Shiflet, 1994), or Brown et al., (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c.

70D. Ultimate expression of chino grama semidesert grassland- Relict xeric foothills grassland dominated by chino grama with black and sideoats grama, red threeawn, bush muhly, and cane bluestem locally plentiful (but not dominant). Shrubs included creosotebush (most common; regional dominant of Chihuhuan and Sonoran Deserts Region), cane cholla, Englemann's pricklypear, and Spanish dagger. Occasional woody legumes (limited to Acacia and Mimosa species). No forbs "to amount ot anything".

Large specimens of chino grama suggested relatively old age (and certainly no lack of plant vigor). Chino grama is a cespitose species unlike the stoloniferous black grama that is the most common dominant of semidesert grasslands. The openness and proportion of unvegetated ground surface of this pristine chino grama grassland vegetation can be compared to the more "closed" (less bare ground) of virgin black grama grassland range shown previously.

Big Bend National Park (foothills, Burro Mesa), Brewster County, Texas. June, early estival aspect (prior to initiation of grass growth). FRES No. 40 (Desert Grasslands Ecosytem). No Kuchler (1964, in Garrison, 1977), Society for Range Management (Shiflet, 1994), or Brown et al., (1998) units applied. Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c.

71. Local stand of chino grama- Appearance of cespitose chino grama or "chinograss" in a local small population. These individual plants were growing on a patch of ground that had been disturbed a few years previously. Plants were relatively small (and presumedly younger) which permitted more detailed observation of species features.

Pebbly soil surface closely resembled desert pavement. The uniform pattern of dispersion is typical of xeric environments. These plants of chino grama were dispersed uniformly as are some of the desert shrubs like ocotillo.

Chinati Mountains, Presidio County, Texas. June, and plants still dormant awaiting summer rains.

74. Racemes of chino grama- Last season's inflorescences on chino grama. Racemes of chino grama resemble those of hairy grama, but the portion of rachis that extends beyond spikelet attachment is thicker in chino grama.

Chisos Mountains (Green Gulch, Big Bend National Park), Brewster County, Texas. June.

75. Gyp(sum) grama (B. breviseta)- Sexual shoots of gyp grama growing on a gyp range site on a three-way ecotone of mixed prairie, semidesert grassland, and "island" of Chihuhuan Desert. B. breviseta and B. ramosa are very closely related. They so closely resemble each other that Silveus (1933, p. 428) and Hitchcock and Chase (1951, ps. 541-542) showed the two binomials as synonyms. Gould (1975, p. 351) followed suite and lumped them together even as he noted that plants growing on gypsum flats tended to have a different or distinct growth habit. Hitchcock and Chase (1951, p. 542) specified an edaphic environment of "gypsum sands and calcareous rocks". Since the original New Mexico Flora of Wooton and Stanley (1915, p. 87) B. brevisita and not B. ramosa have been cited for Trans Pecos New Mexico. In the equally classic, seminal, and even earlier work, Botany of Western Texas Coulter (1891-1894, p. 530) described and distinguished both B. breviseta and B. ramosa for Trans Pecos Texas. The two taxa were treated as separate species by Correll and Johnston (1979, ps. 246-247) and Powell, (2000, ps. 216-218) with the former declaring both to be present in southern New Mexico. Powell (2000, p. 216) specified that B. brevisita appeared to be an obligate glysophile (organism restricted to gypsum soils) and cited Reeder and Reeder (1980) who reported that B. breviseta was diploid whereas B. ramosa was tetraploid.

Lastly (though by no means the last word), Barkworth et al. (2003, ps. 253, 267-268) as the official--though not necessarily the correct--encyclopedic treatment of North American Gramineae, distinguished B. breviseta from B. ramosa based largely on the detailed work of Reeder and Reeder (1980). Both species were reported for Texas and northern states in Mexico, but B. ramosa was not shown for New Mexico though it was mapped in adjacent Texas counties. Barkworth et al. (2003, p. 253) specified dichotomous morphological differences as a presence vs. absence of chalky bloom on shoots and presence vs. absence of rhizomes, B. ramosa being strictly cespitose. Dichotomous habitats stated in Barkworth et al. (2003, p. 253) were limestone soils (B. ramosa) vs. gypsum soils (B. breviseta). This is perhaps one of the most distinct separations of grass species as to edaphic environment, a textbook example. These differences corresponded to differences in ploidy (tetraploid vs. diploid for limestone-derived vs. gypsum-derived soils).

Railway Ranch, Upton County, Texas. Mid-October; early stage of dormancy.

76. A needlesome grama- Needle grama (B. aristidoides) is one of three annual Bouteloua species that calls semidesert grasslands and Chihuhuan Desert its home (Gould, 1975, ps. 341, 344, 346). And yes indeed, it does closely resenble threeawn (Aristida) species. Needle grama occurs in disturbed and otherwise marginal environments from the Rio Grande Plains up through the Edwards Plateau throughout the Trans Pecos Basin and Range vegetational areas (Gould, 1975, p.341 ). The current author photographed this specimen on silver bluestem-sideoats grama mixed prairie in the High Plains vegetational area of Texas where it, the Rolling Plains, and northwestern edge of Edwards Plateau converge (Gould, 1963; Correll and Johnston, 1979, map 1).

Forage value of this like the other annual gramas varies from fair when immature to poor at maturity as seen in these photographs.

Howard County, Texas. Mid-October; grain-ripe stage and nearing end of plant life.

77. Generalized pattern of range vegetation zonation in mountains of Trans-Pecos Texas- The author's view of zones of range plant communities in the Trans-Pecos Texas Basin and Range physiography. Zonation coincided largely with elevation, but there were assuredly numerous factors at work in development of this climax vegetation that was interpreted here in terms of range cover (= dominance) types.

Ponderosa pine and oak-pinyon-juniper range types were covered in chapters of Forests and Woodland Biomes.

78. Semidesert grassland at upper elevational limit- The black grama upland form of semidesert grassland described earlier extends up the slopes of several mountain ranges in the Trans- Pecos Basin and Range province. At these higher elevations more mesic species (those more characteristic of either semiarid climates to the east and/or west of the Chihuhuan Desert) become more abundant, often becoming local dominants. This includes grasses like little and silver bluestem, sideoats and blue grama and tanglehead (Heteropogon contortus). The same pattern of plant distribution at higher elevations occurs for shrubs with Mormon tea, soaptree yucca, fourwing saltbush, and mesquite from the lower grasslands joined by mountain mahogany (Cercocarpus montanus), skunkbush sumac (Rhus trilobata), and Apache plume (Fallugia paradoxa) from the encinal or montane scrub (Dick-Peddie, 1993, ps. 123-128).

The developing thunderhead (early stage of a cumulonimbus cloud) was representative of the major source of precipitation during the summer portion of the growing season in the southern Basin and Range province. Fortunately for an area receiving only 7-10 inches of annual precipitation a high proportion of this moisture falls during the mid- to late-growing season. Most of this is delivered by local thunder showers (usually of short, but often intense, duration) in which hail may accompany rain. Some authorities interpret this summer pattern as part of the monsoonal flow characteristic of the Sonoran Desert. Thunder showers are local in nature in contrast to general or widespread precipitation from large cyclonic storms or frontal systems. Thunder showers often develop sporadically within a general high pressure system with any precipitation being formed by condensation of water that arose by evapotranspiration below. If a thunderhead builds and "lets loose" above a given locale that part of the range benefits. Otherwise it remains "high and dry" (ie. thunderstorms are a "hit and miss" affair).

79. Apache plume (Fallugia paradoxa)- Fruit and leaves of a valuable mountain browse plant. This is one of many genera and species in the Rosaceae. The rose family furnishes the largest number and the most valuable species of browse plants in North America. Apache plume is an important feed species and is tolerant of heavier browsing but it's palatability usually varies from low to moderate sometimes ranking as high as good for both cattle and sheep (Dayton, 1931, ps 50-52; Forest Service, 1940, B77). Apache plume is most important on winter range.

Lincoln County, New Mexico. June.

80. Classic example of the Upper Sonoran life zone of C. Hart Merriam in the Trans-Pecos Basin and Range— This is in the Chihuhuan Desert, but it is a transition range type from semidesert grassland to the desert shrubland to be seen below.Lechugilla (Agave lecheguilla)-Chino grama (Bouteloua ramosa)- creosotebush (Larrea tridentata= Covillea tridentata ) type. Limestone and mountains range site.

This range cover type was included here to illustrate the adjacent location of Chihuhuan Desert and semidesert (Chihuhuan) grassland and the mosaic of vegetation formed by this "patchy" occurrence of these two biomes in the greater Chihuhuan Region. This spatial arrangement is especially noticeable in Texas' Trans-Pecos Basin and Range Vegetational Area.

While this community has features of FRES Nos. 30 (Desert Shrub Ecosystem) and 40 (Desert Grasslands Ecosystem) it most closely fits FRES No. 33 (Southwestern Shrubsteppe Ecosystem) with the closest corresponding Kuchler unit being K-52 (Gramagrass-Tobosagrass Shrubsteppe[without the Tobosa]). No specific SRM cover type description; closest is variant of SRM 505 (Grama-Tobosa Shrub). Mixed Grass-Scrub Series of Brown et al. (1998). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).

81. Lechuguilla (Agave lechuguilla)- This is probably the most abundant Agave species in the Trans-Pecos Basin and Range area. In fact, lechuguilla "has one of the most extensive ranges of the agaves" (Gentry, 1982, p. 154). Lechuguilla is also one of the most easily identified (usually recognized immediately) by the high number of rosettes growing in clusters or groups. A. lechuguilla is a highly modular organism. Each of the basal rosettes is a module (a clone= ramet) of a genetic indivisual (genet). Most reproduction is asexual via suckering from rhizomes or rhizome-like structures (ie. "rootstocks"). Gentry (1982, p. 154) stated that numbers of rosettes "probably exceed those of all other native agaves". Gentry (1982, ps. 30-31) described the Agave rosette.

Incidentally this wonderful book, Agaves of Continental North America, (Gentry, 1982) is the encyclopedia and definitive reference by the man regarded as the world expert on Agave. Expensive, but well worth the price to any succulent-lover.

Lechuguilla is a poisonous range plant that has been documented to poison cattle, sheep, and goats, and--no surprise--this poisoning takes place under conditions of overgrazing. Gentry (1982, p. 157) delightfully described such mismanagement concluding that lechuguilla is "a protective agent of the range, penalizing those stockmen who, through force of circumstance or lack of foresight, decimate their resource by over-use". AMEN! The poisonous principle in lechuguilla is a saponin that causes hepatogenic or secondary photosensitization due to liver damage. References include Kingsbury (1964, ps. 56, 467-468), Sperry et al. (1964, ps. 7-8), Burrows and Tyrl 2001, 13-15), and Hart et al. (2003, 22-23).

Taxonomic treatment of Agave has been controversial. Traditionally the genus has been included in the agave family, Agavaceae, (eg. Powell, 1988), but other workers (eg. Smith, 1977) placed Agave in the lily family, Liliaceae, as an agave subfamily, Agavoideae. Incidentally, is there anything that is not controversial when it comes to plant taxonomic treatments?

Hudspeth County, Texas. June.

82. Basal rosettes of lechuguilla- Example of a cluster of rosettes, asexual modules of a genetic individual of lechuguilla. It was explained in the immediately preceding photo-caption that lechuguilla probably produces more rosettes than any other Agave species in North America. Recall from that explantion that each such rosette is a clone (= module= ramet) of the original "parent plant" which is the genet. Gentry (1982, p. 30) explained that each rosette of A. lechuguilla is a "monocarpic rosette". Each rosette flowers only once in its life (the life of that clone or module) and then dies; in fact, it begins to die as soon as the one-time flower stalk with its inflorescence begins to emerge and elongate. This condition was obvious in the flowering rosette in the cluster shown in this photograph. The inflorescence on this particular stalk was presented in the immediately succeding photograph.

With this pattern of life cycle and resource allocation, each genetic individual (the genet or actual unique plant) of lechuguilla with its ramets (rosettes) is a "multiannual" (Gentry, 1982, p. 30). Gentry's choice of terms could confuse the beginning student. Yes, the individual rosette flowers only once in its life and then promptly dies. The flowering-seed production process takes only a few weeks as flower stalk growth is extremely rapid (perhaps over a foot a day) such that this phenological development is "annual" (more like "ephemeral"). Yet it takes years (perhaps a quarter century) of reserve food storage, rosette growth, and formation of stalk primordial tissue development before flowering can be initiated. In reality each rosette is a long-lived perennial that finally flowers and then summarily dies. With asexual (vegetative or clonal) reproduction the genetically unique plant has a life span that is seemingly "endless" or "forever". The only thing annual about an Agave species is the amazing flowering and fruit production phenomenon. And that is phenomenonal.

85. Alkali sacaton-shrub savanna- Alkali sacaton was the dominant species on this saline swale, but it "kept company" with numerous shrubs including whitethorn acacia, fourwing saltbush (Atriplex canescens), lotebush (Ziziphus obtusifolia), honey mesquite, and mariola. The most common forb was the Eurasian annual weed, tumbleweed or Russian thistle (Salsola kali-tenuifolia= S. iberica= S. pesitfer= S. tragus). Other grasses included inland saltgrass (Distichlis spicata var. stricta= D. stricta), tobosagrass, cane bluestem, and naturalized Johnsongrass (Sorghum halepense).

It appeared that grass cover was considerably less and woody plant cover more than in the natural plant community. In fact this bottomland range was closely located to a mining and early settlement site so that all matter of human disturbance could have impacted this plant community. It is also probble that some, if not all, of these shrub species had been present at lower cover percentages in the virgin range vegetation. Introduced species like Russian thistle and Johnsongrass were not components of pre-Columbian vegetation, but must be assumed to be new components of the potential natural vegetation for an indefinite period of time.

Presidio County, Texas. June: warm-season perennial grass species were still in dormancy just bvefore typical onset of summer rains. FRES No 40 (Desert Grasslands Ecosystem). Natural vegetation of this small spatial dimension was not mapped by Ku;chler (1964, in Garrison et al., 1977). Variant of SRM 701 (Alkali Sacaton-Tobosagrass). Brown et al. (1998) erroneously omitted the Sacaton Series from Chihuhuan (Semidesert) Grassland under Warm Temperate Grassland, but this is what this range plant community was. Maybe there will be a second, revised, and expanded edition of Brown et al. (1998) that will include such a Sacaton series. Chihunuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004). Degraded Salty Bottomland range site.

86. Detail of range vegetation on a local saline swale- Alkali sacaton was the dominant herbaceous species. Other grass species included inland saltgrass, tobosagrass, cane bluestem, Johnsongrass. Shrubs included lotebush (branches at extreme right margin) and (not visible in this photogrph) whitethorn acacia, mesquite, fourwing saltbush and mariola. The most common forb was Russian thistle or tumbleweed, a specimen of which was is left foreground.

Traces of encrusted salt on the soil surface were visible. It was likely that human-induced disturbances associated with local mining and settlement result in loss of grass cover and increased cover and density of shrubs, but there was no range reference area for comparison. Range vegetation shown here was still an example of one form of saline, alkaline, and/or gypsous soils on low-lying range sites generically referred to as "swales", "flats", or "sinks".

Presidio County, Texas. June: still dormant season for summer-growing perennial grasses. FRES No. 40 (Desert Grasslands Ecosystem). Smaller units of range vegetation such as this were not mapped by Kuchler (1964, in Garrison et al., 1977). Variant of SRM 701 (Alkali Sacaton-Tobosagrass). Sacaton Series under Chihuhuan (Semidesert) Grrassland 143.1 of Warm Temperate Grassland 143 if and when one is listed under a revision or expanded edition of Brown et al. (1998); an error that Sacaton Series was not so listed. Chihuhuan Deseerts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004). Salty Bottomland range site in some degree of range depletion.

88. Sacaton swale-Sporobolus giganteus and S. wrightii (giant and Wright's sacaton) form a grassland due to runoff form surrounding shallow slopes.Another local edaphic or perhaps hydric climax.

On the virgin range big or giant sacaton (S. wrightii) occurred as immense sacaton flats in more moisture-favorable swales, seepage areas, or infrequently flooded semidesert grasslands. This range type deveoped on cienegas that have been designated sacaton riparian grasslands (Tiller et al., 2012). Cienaga (or cienega) was defined in Wilson and Moore (1998) as: "A marshy area where the ground is wet due to the presence of seepage or springs, where the water is at or near the sufrace. It often has standing water and abundant vegetation The term is commonly applied in area regions such as the southwestern US. Etymol: Spanish cienaga, 'marsh, bog, miry place'".

Eddy County, New Mexico.FRES No. 40 (Desert Grasslands Ecosystem). Variant of SRM 701 (Alkali Sacaton-Tobosagrass). Chihuhuan Deserts- Edge of Chihuhuan Basins and Playas Ecoregion, 24a (Omwenik and Griffith, 2006).

89. Wright's sacaton (Sporobolus wrightii)- A large specimen of Wright's sacaton on a sandy bottomland at edge of Chihuhuan Desert. This species has only intravaginal shoots which are termed tillers. Tillers of S. wrightii are smaller in diameter and more numerous than is the case for S. giganteus.

Cox (1984, 1985) reported on shoot yield (biomass) in S. wrightii. The value of big or giant sacaton was obvious enough that the Natural Resources Conservation Service and New Mexico State University at the Plant Materials Center, Los Lunus, New Mexico developed and released the cultivar, "Windbreaker" (Natural Resources Conservation Service 2011). Natural Resources Conservation Service (Lloyd-Reilly, 2011) also prepared a Plant Fact Sheet on big sacaton. S. wrightii was treated briefly by Gould (1975, ps.301) and later (and also briefly) by Shaw (2012, p.943). Powell (2000, ps. 193-194) provided somewhat more coverge and gave big sacaton a Fair forage value rating but then added "it is of greater value in areas where it is abundant and dominant".

Elephant Mountain Wildlife Management Area, Brewster county, Texas. June, full-bloom stage.

91.   Alkali sacaton flat- Throughout the southwestern deserts and back into the southern mixed prairie there are some alluvial sites, especially swales and flood plains and (even more) saline or alkaline flood plains, that are dominated by alkali sacaton (Sporobolus airoides). While this species is widely distributed ranging as far as the tallgrass prairie region (eg. in Missouri) and up in the northern Great Plains of Montana, it is on overflow sites in the southern part of the arid and semiarid regions where alkali sacaton forms essentially single species stands (= consociations) which are priceless as natural sources of livestock forage, wildlife habitat, and flood control.

These “sacaton flats” or “sacaton swales” are distinct from and more widely occurring than those formed by giant and Wright’s sacaton which were shown immediately above. Also, alkali sacaton occurs in association and often as a co-dominant with other bottomland or flood plain species as for example in SRM Rangeland Cover Types 701, 702, 712, and 725. Interestingly (strangely to this author), the Society for Range Management in it’s publication on cover types (Shiflet, 1994) did not recognize the widely distributed “pure form” or “pure stand” of alkali sacaton flat. The closest would likely be a variant of SRM 701. Likewise, this range type is entirely too restricted to have been described separately as a FRES unit and too small to have been mapped by Kuchler. Sacaton flats (those of any or all such Sporobolus-dominated alluvial sites) are local range types under both FRES No. 38 (Plains Grassland Ecosystem) and No. 40 (Desert Grasslands Ecosystems), and perhaps as localized grasslands within FRES No. 30 (Desert Shrub Ecosystem).

Dick-Peddie (1993, p. 105) noted presence of swales co-dominated by tobosagrass and alkali sacaton (SRM 701) which he placed under the “Tobosa Series (swales)”, but he also showed a S. airoides-dominated flat which he presented as “Sacaton Series (swales)” (Dick-Peddie, 1993, p. 110). Alkali sacaton swales composed exclusively of this one species is a well-known range type and this cover type should have been included in the SRM rangeland cover type manual (Shiflet, 1994). 

“Proof-positive” of the existence of S. airoides consociations that form alkali sacaton flats is presented here in this photograph of a flood plain in the Texas Trans Pecos Basin and Range Region. Reeves County, Texas. October. Chihuhuan Deserts- Chihuhuan Desert Grasslands Ecoregion, 24b (Griffith et al., 2004).

93.  Border of an alkali sacaton swale- Along the perimeter of the alkali sacaton flat seen above, Sporbolus airoides was joined by two (two other) halophytes:  pickleweed (Allenfrofea occidentalis), center-most and largest plant, and glasswort or Utah samphire (Salicornia utahensis), left foreground. 

Reeves County, Texas. October.

97  Alkali sacaton (Sporobolus airoides)- Alkali sacaton is one of the largest and most productive of the dropseed species. It often dominates alluvial or flood plain sites from the southern Great Plains into the Chihuhuan and Sonoran deserts where fertile soils and relatively high soil moisture form an edaphic environment that is postclimax to the regional vegetation. These soils are often higher in dissolved minerals thereby being saline or alkaline habitats. As indicated by its common name, alkali sacaton is well-adapted to these conditions and able to exploit the favorable soil water content. The specimen seen here is stunted by a combination of a severe drought and overutilization by cattle, but the otherwise healthy, vigorous condition of this depauperate specimen attest to the species adaptation to both conditions. (Trade secret for beginning plant photographers: diminutive specimens frequently— even typically —make the best shots of non-photogenic species like most grasses because both basal portions and flower clusters are easier to bring into crisp focus.)

Reeves County, Texas. October.

Vine mesquite (Panicum obtusum) "flat", swag, or swale- Swales and flood plains make up some of the more restrictive-- yet distinctive and productive-- groups of semidesert grasslands. This is actually a category or general grouping of several forms or kinds of "desert plains grasslands". The tobosagrass-dominated semidesert grasslands (= "tobosa flats" or "tobosa swales") comprise the most extensive of these (it was appropriately dealt with first in above coverage). "Sacaton flats" is another category of generally mesic-habitat semidesert grasslands determined and identified according to the one or two dominant Sporobolus species (and sometimes including inland or desert saltgrass and halophytes like pickleweed or fourwing saltbush). This form of swale semidesert grassland was treated immediately above.

A third range cover (= dominance) type defined by the swale, swag, flat, or flood plain topography and identified as to dominant species is that of vine mesquite.A vine mesquite consociation is, alternatively, SRM 725 (Vine Mesquite-Alkali-Sacaton), a variant of SRM 725, or a separate Vine Mesquite rangeland cover type. The latter alterntive was consistent with this author's interpretation of SRM 505 (Grama-Tobosa-Shrub) as too general and, thus, consequent separation of it into a Black Grama rangeland cover type and a Tobosagrass rangeland cover type.

101. Vine mesquite flat or swale- A consociation (Clementsian term for single-species stand) of vine mesquite developed on a mesic bottomland lying between upland sand ridges vegetated by depleted black grama semidesert grassland range. The rangeland in this and the next three photographs was on the former El Camino Real, the "Kings Road" or Royal Road" from Santa Fe to Chihuhua City. This range vegetation had somehow persisted or recovered from impact of trade and travel over almost 300 years, but upland semidesert grassland range was Chihuhuan Desertscrub disclimax. What, if any, influence upland range plant communities had on the grassland on this "flat" was not known. What was known is that vine mesquite-dominated grassland had persisted for decades under cattle grazing (background, and next slide) and protection from large animal grazing.

This vine mesquite semidesert grassland was intepreted as climax vegetation and an example of a range reference area. For all practical purposes vine mesquite was the only plant species on this range. Tobosagrass was plentiful on lower elevation and depression microsites to the right of camera range (not in photograph).

Vine mesquite in foreground was in a livestock exclosure. For decades this range vegetation had not been grazed by livestock (native ruminants could possibly have grazed inside exclosure; rodents and lagomorphs most certainly did consume some of the exclosue herbage).

New Mexico State University College Ranch, Dona Ana County, New Mexico. June, early estival aspect and pre-bloom phenological stage.FRES No. 40 (Desert Grasslands Ecosystem). No appropriate units of vegetation by Kuchler (1964, in Garrison et al., 1977) or Brown et al.(1998). Vine Mesquite variant of SRM 725 (Vine Mesquite-Alkali Sacaton). Chihuhuan Deserts- Chihuhuan Basins and Playas Ecoregion, 24b (Omernik and Griffith, 2006).

107. The difference is utilization- Fenceline difference in degree of use. Vegetation on right had been excluded from livestock entry for decades (approximately 70 years); range vegetation on left had been subjected to cattle grazing for an even longer period of time. While the difference is a stark contrast, it is a difference primarily in degree of use and not of plant species composition. Plant communities on both sides of the exclosure fence were single-species stands of vine mesquite. This should be obvious to careful viewers.

First Cardinal Principle of Range Management: Proper Degree of Use.

Even though utilization (= degree of use) seemed to be of some heavy (even suggestive of excessive) grazing use vine mesquite had persisted under this approximate grazing regime (seasonal suitability grazing at what was interpreted by on-the-graund rangemen as "moderate" rate) for many years.

Third Cardinal Principle of Range Management: Proper Season of Use.

It is likely that the greater soil moisture of this swale permitted heavy-- at least, heavier--utilization and continued survival of and comparatively high herbage yields by vine mesquite.

Brangus cattle of the New Mexico State University purebred herd. Brangus is one of the best-adapted beef breeds for semidesert grassland range due to superior rustling ability includning covering rough country and traveling relatively long distances to water. Exceptional maternal features (mothering and milking ability) is another strong point of Brangus.

Fourth Cardinal Principle of Range Management: Kind and Class of Range Animal. This includes selection of superior breeds within the proper species (Bos taurus X B. indicus cross in this instnce) and the proper sex, age, or market class (cows and calves in this case).

New Mexico State University College Ranch, Dona Ana County, New Mexico. June, early estival aspect and pre-bloom stage. FRES No. 40 (Desert Grasslands Ecosystem). Kuchler (1964, in Garrisonet al., 1977) did not map units of vegetation at spatial scale of this range cover type. No descriptive biotic community in Brown et al. (1998). Vine mesquite variant of SRM 725 (Vine Mesquite-Alkali Sacaton).

103. Botanical compostion and sward of vine mesquite flat- Species make-up and local physical appearance of vine mesquite consociation on a swale or mesic flat on semidesert (Chihuhuan) grassland. The only perennial plant of any abundance was vine mesquite. The most obvious perennial forb was one of the narrowleafed rosin or horsetail milkweed Asclepias subverticillata). The two species of dead plants conspicuous in the second slide were both winter annuals: tumble mustard (Sisymbrium altissimum) and an unidentifiable composite.

Noteworthy was the development of a closed canopy sward-- a turf-- of essentially 100% foliar cover in an area receiving an average of eight inches in annual precipitation. Grains on the fruiting shoot tips of vine mesquite were visible (at least at regular projection of the 35 mm slide).

New Mexico State University College Ranch, Dona Ana County, New Mexico. June, early estival aspece and pre-bloom phenological stage. FRES No. 40 (Desert Grasslands Ecosystem). No vegetation units in Kuchler (1964, in Garrison, 1977) who used larger mapping units than this. Vine mesquite variant of SRM 725 (Vine Mesquite-Alkali Sacaton). No appropriate biotic community in Brown et al. (1998): vegetation classification and mapping remains a "work in progress".

104. Stand of vine mesquite at peak standing crop- A luxurious verdent turf of vine mesquite like this one is seldom produced in the semidesert grassland, and this was no exception. This stand grew in the Western Cross Timbers of northcentral Texas, but it did illustrate appearance of vine mesquite under optimum growing conditions and the wide range of habitats, including precipitation zones, under which this panicoid species can achieve dominance.

Tarleton State Univrsity Hunewell Ranch, Erath County, Texas. July.

105. Vine mesquite- Dense stand of vine mesquite showing characteristic sward of this valuable mid-grass. This panicgrass is adapted to a diversity of habitats ranging from understory species in the Texas Cross Timbers through to the rock-strewn shallow ranges of the Edwards Plateau and the floodplain and bosques of semidesert grasslands of the Southwest. Vine mesquite is usually a decreaser and fairly productive of palatable and reasonably nutritious forage when green but when mature it cures with lower nutritive value than associated shortgrasses like buffalograss or blue and black grama.

Vine mesquite produces both stolons and rhizomes such that is a pronounced sod-forming species. This sward was on a lowland site of Windthorst soil, Hunewell Ranch, Tarleton State University, Erath County, Texas, June.

107. Less viney than some- A single plant of vine mesquite growing in the West Cross Timbers of northcentral Texas during one of the most one-year droughts on record (at least 14 weeks of Exceptional Drought, the highest or worst category on the Palmer Drought Severuity Index). This plant was growing on a range that had been (was being) grazed by white-tailed deer as the only large mammalian grazer. Deer had not fed on vine mesquite. This was an example of the state of a native, decreaser grass when undefoliated by animals in the worst of drought.

This example demonstrted that if ranchers could destock and move livestock to ranges less impacted by drought the native range plants could survive quite handily. This one appeared to be thriving even under Exceptional Drought. Some readers might object to this hypothetical situation alledging that such an emergency measure would be impractical because everyone else was out of feed and there would be no range to rent at any price. OK, so what to any such objectors propose? Eat what grass is left into the ground and then have to destock anyway when that is gone? Talk about impractical! All that all-too-common mismanagement amounts to is absence of feed even when rains return (as they always do). That foolishness just leaves ranchmen without forage and livestock. Stockgrowers are, at the most fundamental level of animal production, grass growers. Grass (generic, poetic for forage) not animals is the basis of ranching. Animals (livestock or wildlife) are the commodity, but grass is the crop, the primary product. Animals are the secondary product, and that commidified secondary product can be only as good as the fundamental crop.

Returning to the crop species featured here, it was remarked that vine mesquite is often a major forage species on various range sites from tallgrass prairie and savanna through mesic habitats on semidesert grassland in both the Chihuhuan and Sonoran Desert Regions. Vine mesquite extends from the prairies of Illinois westward to Utah and south into Mexico. Vine mesquite is widespread--on mesic environments--thoroughout much of the vast Basin and Range Physiographic Province beginning with the Trans Pecos poration.

This particular vine mesquite plant had not produced long stolons, but it had produced a high yield of caryopses that were in the early hard-dough stage. Again, this grain crop was in the worst one-year drought in Texas history (as of this writing).

Tarleton State University, College Farm, Erath County, Texas. Late September.

108. Look what I did in record drought- Panicles filled with ripening grain of vine mesquite growing in the West Cross Timbers of northcentral Texas in the worst one-year drought on record (more than 14 weeks of Exceptional Drought, D4 on the Palmer Drought Severity Index). In the Paniceae (panicgrass tribe of the Panicoideae) spikelets are solitary (unpaired) and consist of two florets, one perfect or fertile and the other, which subtends (is below) the perfect, is sterile. The sterile floret is reduced to an empty lemma which resembles a glume. The lemma and palea of the fertile (perfect) floret are indurate ("hard").

In vine mesquite the entire inflorescence is a racemose panicle. Gould (1975, p. 452) described this flower cluster as a "narrow, contracted panicle or raceme". The inflorescence was regarded as a panicle with "... main branches appressed and sparingly rebranched" by Great Plains Flora Association (1986, p. 1203). These features were visible in these two photographs.

All-in-all, a very pretty--and an extremely drought-tolerant--species.

Tarleton State University, College Farm, Erath County, Texas. Late September; early hard-dough stage.

109. Horsetail or rosin milkweed (Asclepias subverticillata)- This narrow-leafed species of milkweed is one of the definitively proven toxic species of Asclepias. Specific references to A. subverticillata include Kingsbury (1964, p.267-268), Schmutz et al. (1968. ps. 24-25), Stephens (1980, p. 85), Burrows and Tyrl (2001, ps. 126-135 passim), and Hart et al. (2003, p. 38-39). Exact toxin in A. subverticillata remains uncertain(Burrows and Tyrl (2001, p. 132-133). From veterinary medicine standpoint the definitive authority is The Merck Veterinary Manual, but even the 50th Anniversary Edition (Kahn, 2005).

This specimen was growing in the vegetation of the vine mesquite swale inside an exclosure on New Mexico State University College Ranch. June.

112. A hard one to pigeon-hole- A bunchgrass-shrub steppe that was a transitional (ecotonal) grassland between semiarid plains-mesa mixed prairie and the most xeric mixed grass-shrub form (variant) of semidesert grassland in the Colorado Plateau. Major range plant species--with no obvious dominant--included blue grama (Bouteloua gracilis), alkali sacaton (Sporobolus airoides), red threeawn (Aristida longiseta), sandhills muhly (Muhlembergia pungens), Indian ricegrass (Oryzopsis hymenoides), and winterfat (Eurotia lanata). Winterfat was abundant and conspicuous enough to give a savanna physiogonomy to this range vegetation. There were a few plants of some pricklypear (Opuntia sp.) that could not be identified to species level. The author could not find any plants of galleta (Hilaria jamesii) on this range. Given aridity of climate, xeric nature of this upland habitat, density and cover of plants, this bunchgrass-shrub savannah had to be interpreted as a range plant community of the Arid Zone, and thus a savanna form or variant of semidesert grassland.

Although plant cover was extremely low (extremely sparse for grassland) on this range, the species composition of this plant community consisted almost exclusively of species that were decreasers for this range site and with almost no presence of annual invaders like Russian thistle Vigor and size of herbceous plants--thus foliar cover--was greatly reduced in an on-going Extreme to Extraordinary Drought (Palmer Index). This rangeman had no option other than to interprete this as climax vegetation, and all things considered a beautiful range. Beyond doubt, this range had received proper husbandry in recent management history. It was such a "pretty" sample of properly managed semidesert grassland range that another view was presented and described further in the next slide-caption set.

Bernalillo County, New Mexico. Mid-July; estival aspect. FRES No.40 (Desert Grasslands Ecosystem). K-47 (Grama-Galleta Prairie), a variant form without galleta. No rangeland cover type (Shiflet, 1994): a galleta-missing variant of SRM 502 (Grama-Galleta). Mixed Grass-Scrub Series 143.14 of Chihuhuan (Semidesert) Grassland biotic community 143,1 of Brown et al. (1998, p. 40). Arizona/New Mexico Plateau- Albuquerque Basin Ecoregion, 22m (Griffith et al., 2006).

113. Defiant grassland- A second view of a bunchgrass-shrub steppe range that was an ecotonal grassland, a vegettional transition between semiarid plains-mesa mixed prairie and the most xeric mixed grass-shrub form (variant) of semidesert grassland in the Colorado Plateau. Major grass species, and with no overall dominant, included blue grama, sandhills muhly, alkali sacaton, Indian ricegrass, and red threeawn. Winterfat was the sole shrub species, but it was of such abundance that this range vegetation was a savanna with a prominent savanna physiogonomy. This "phototransect" feature an extra-large specimen of sandhills muhly (too tempting a target for this rangeman to omit from this collection).

This range plant community was obviously (at least to this author) the climax vegetation for this range site.Sparcity of range plant cover was attributed largely to limited herbage (and even foliage of winterfat) due to ou-going drought that was rated (Palmer Scale) as Extreme to Extraordinary. This limited herbaceous or foliar cover was demonstrated vividly by the individual of snadhills muhly which, even though it had immense basal cover (over ten feet across the circle of basal shoots), had extremely scant size of clonal units. The fact that the outer edge (margin) of this individual clonal plant was still intact with an uninterupted "ring" of basal shoots was proof that grazing had been proper and that utilization (degree of use) had been "light enough" (of comparatively low intensity of defoliation) that the modules or ramets (clonal units) were still alive (again, in Extreme to Extraordinary Drought).

Range plants can survive tremendous stress if they are properly managed. This range had not been grazed during the current growing season.

Bernalillo County, New Mexico. Mid-July; estival aspect. FRES No.40 (Desert Grasslands Ecosystem). K-47 (Grama-Galleta Prairie), a variant form without galleta. No rangeland cover type (Shiflet, 1994): a galleta-missing variant of SRM 502 (Grama-Galleta). Mixed Grass-Scrub Series 143.14 of Chihuhuan (Semidesert) Grassland biotic community 143,1 of Brown et al. (1998, p. 40). Arizona/New Mexico Plateau- Albuquerque Basin Ecoregion, 22m (Griffith et al., 2006).

The next section was devoted to semidesert grasslands in the Great Plains-Great Basin transition zone. The adjective Navahonian (Navajonian) was in reference to both: 1) Navahonan section of the Colorado Plateau physiographic province (Fenneman, 1931, ps. 312-317; Thornbury, 1965, ps. 431-434).and 2) Navahonan biotic province of Dice (1943) and as applied specifically to natural plant communities (Lowe, 1964, ps. 91-96).

This form probably reaches its best expression over a large area in northern, especially northeastern, Arizona. Semidesert grasslands in southern Arizona and southeastern Calironia are in the Sonoral biotic province of Dice (1943) and are in the Basinand Range physiographic province as are those that develop in a mosaic with the Chihuhuan Desert eastward..

114. Lots of land and lava- Landscape-scale views of semidesert grassland at edge of Grants Malpais in Colorado Plateau. Range vegetation was a mosaic, a patchwork, of various grassland and grass-shrub steppe communities comprised variously of black grama (Boutelous eriopoda), sideoats grama (B. curtipendula), blue grama (B. gracilis), galleta (Hilaria jamesii), and alkali sacaton (Sporobolus airoides) --the major grasses (all of subfamily, Eragrostoideae)--with fourwing saltbush (Atriplex canescens) and winterfat (Eurotia lanata)--the major shrubs (both of saltbush family, Chenopodiaceae). Dominance--always by grasses--varied at local scale, but black grama was the overall dominant species with sideoats grama being the major associate (though sometimes co-dominant with black grama). Fourwing saltbush was more abundant than winterfat.

Land ownership was mixture of Federal (Bureau of Land Management, National Park Service) and private property. Cibola County, New Mexico. Mid-July; early estival aspect in Extreme Drought (Palmer Index). FRES No. Desert Grasslands Ecosysstem). K-47 (Grama-Galleta Steppe). SRM 502 (Grama-Galleta) or, alternatively, SRM 703 (Black Grama-Sideoats Grama) and some small patches of SRM 702 (Black Grama-Alkali Sacaton): transition zone between SRM 502 and SRM 703/702. Warm Temperate Grassland 143, Chihuhuan (Semidesert ) Grassland 143.1, Mixture of Grama Grass-Scruub Series 143.11 and Mixed Grass-Scrub Series 143.14 of Brown et al. (1998, p.40). Arizona-New Mexico Plateau- Lava Malpais Ecoregion 22k (Griffith et al., 2006).

115. Living on lava- Range plant community of sideoats grama, the dominant species, with black grama and blue grama as associate species along with fourwing saltbush, dominant shrub, and some winterfat on a relict tract of semidesert grassland that developed on Grants Malpais in the Colorado Plateau. This area was on a high hilltop on an interstate highway right of way so it was protected from livestock grazing and served as a de facto livestock exclosure. Obviously the virgin range vegetation.

Land ownership was mixture of Federal (Bureau of Land Management, National Park Service) and private property. Cibola County, New Mexico. Mid-July; early estival aspect in Extreme Drought (Palmer Index). FRES No. Desert Grasslands Ecosysstem). K-47 (Grama-Galleta Steppe). Local area of SRM 703 (Black Grama-Sideoats Grama). Warm Temperate Grassland 143, Chihuhuan (Semidesert ) Grassland 143.1, Mixture of Grama Grass-Scrub Series 143.11 and Mixed Grass-Scrub Series 143.14 of Brown et al. (1998, p.40). Arizona-New Mexico Plateau- Lava Malpais Ecoregion 22k (Griffith et al., 2006).

116. Plant life in the lava beds- Nested "photoquadrants" showing local range vegetation of grass-shrub steppe form of semidesert grassland that developed on Grants Malpais in Colorado Plateau. Black grama and sideoats grama (number one and number two co-dominant, respectively) with fourwing saltbush as the main associate range plant species. These "photoplots" were on a lava hill on right-of-way of an interstate highway so as to be a de facto livestock exclosure. Potential natural (climax) range plant community.

There were numerous species of lichen growing on the basaltic lava on this range. So far there have been 87 species (41 genera in 20 families) of lichen document in El Malpais National Monument (research checklist, El Malpais National Monument, Consortium of North American Lichen Herbaria, J.P. Bennett and C.M. Wetmore).

Cibola County, New Mexico. Mid-July; early estival aspect in Extreme Drought (Palmer Index). FRES No. Desert Grasslands Ecosysstem). K-47 (Grama-Galleta Steppe). Local area of SRM 703 (Black Grama-Sideoats Grama). Warm Temperate Grassland 143, Chihuhuan (Semidesert ) Grassland 143.1, Grama Grass-Scruub Series 143.11 of Brown et al. (1998, p.40). Arizona-New Mexico Plateau- Lava Malpais Ecoregion 22k (Griffith et al., 2006).

117. Living amid lava flows- Sward consisting primarily of black grama with some cover of sideoats grama along with small plant of fourwing saltbush (can you find it?) as a local "photosample" of grass-shrub steppe form of semidesert grassland that developed on Grants Malpais in Colorado Plateau. This "photoplot" was a subset of the range vegetation presented in the two immediately preceding slide-caption sets. This sequel of four photographs went from the largest to smallest spatial scale. This sample of range vegetation was on a interstate highway right-of-way that served as a de facto livestock exclosure. Plant life of this "photoplot" was a representative sample of the otential natural (climax) range plant community of this range site.

Petrolific plant life consisted primarily of lichens. There 87 species (41 genera in 20 families) of lichen recorded for El Malpais National Monument (research checklist, El Malpais National Monument, Consortium of North American Lichen Herbaria, J.P. Bennett and C.M. Wetmore).

Cibola County, New Mexico. Mid-July; early estival aspect in Extreme Drought (Palmer Index). FRES No. Desert Grasslands Ecosysstem). K-47 (Grama-Galleta Steppe). Local area of SRM 703 (Black Grama-Sideoats Grama). Warm Temperate Grassland 143, Chihuhuan (Semidesert ) Grassland 143.1, Grama Grass-Scruub Series 143.11 of Brown et al. (1998, p.40). Arizona-New Mexico Plateau- Lava Malpais Ecoregion 22k (Griffith et al., 2006).

The following section presented a bunchgrass steppe and bunchgrass-shrub steppe form of the semidesert grassland that developed on the Painted Desert section of the Colorado Plateau. This was part of the larger Coloradoan or Navajoan Regional Vegetation of the Colorado Plateau physiographic province. The classsic description of the Colorado Plateau province remains that of Fenneman (1931, ps. 274-325) with a more recent (and, still, classic) treatment by Thornbury (1965, ps. 405-441). General (and much less detailed) treatment of the Colorado Plateau environment was in the collected works edited by Orme (2002, ps. 212-213, 242-243, 395-397). Other outstanding treatments of the Colorado Province from standpoint of its geology are those of Baars (1972, 2000) and Chronic (1983, ps. 176-265).

Most of the examples of the Navajoan form of semidesert (= desert plains) grassland presented in this section were found in Petrified Forest National Park which is in the Navajo section of the Colorado Plateau province (Fenenman, 1931, ps. 312-317). Good treatment of the geology of Petrified Forest National Park was in Chronic (1983, ps 297-299).

The predominant bunchgrass physiogonomy of this range vegetation was reflective of the cespitose habit (tufted due to all or most shoots being tillers) that was the primary morphological form of the eragrostoid (of subfamily, Eragrostoideae) grasses that were dominant and associate species that comprised almost all of the herbaceous vegetation of this semidesert grassland.While some grass species, including the often dominant black grama, are stoloniferous (shoots are stolons) and sodforming (versus bunchgrass or tufted habit of tillering cespitose species) the predominant morphological form is bunched, clumped, or tufted (all synonyms). Even plants of stolonifrerous species like black grama are considerably reduced in individual plant cover due to aridity and limited soil moisture so that the overall physiogonomy (outward appearance) of this grassland is that of a bunchgrass prairie, commonly known as steppe.

Most of the examples presented below were of ranges from which livesstock had been excluded for periods ranging from eighty to over a hundred years down to what appeared to be less than ten years. These example ranges were being grazed or, at least, subject to being grazed by wildlife. It was probably the case that most wildlife species which existed in recent times were still present for grazing/browsing of the example ranges. Range use may have been at lower stocking rates than in the pre-Columbian period. Although the fossil record showed that the prehistoric bovid, Bison latifrons had been present in what is today the state of Arizona (Roe, 1972, p. 18), evidence for the presence of North American buffalo (B. bison) in Arizona is merely suggestive not definitive (Roe, 1972, 260, 275-276). Similarily, there were white man records of buffalo in range country that became eastern Utah (Roe, 1972, ps. 257, 267-268) and eastern New Mexico (Roe, 1972, ps. 257, pages listed on page 980), but it is doubtful that Bison bison occupied what is now Nevada (Roe, 1972, p. 277) or California (Roe, 1972, ps. 281-282) during the post-Columbian time period.

A nearly inescapable conclusion was that --based on records of Anglo-Americans--North American buffalo were not common or abundant on the grasslands or deserts of the Arid Region of North America. What prehistoric mammals may have grazed these semidesert grasslands is known but to God. In final analysis it seemed that examples of desert plains grasslands provided below had likely been overgrazed by livestock of European man, but that those grasslands from which livestock were excluded--some of them for comparatively short periods--had recovered to such degree that the range vegetation approached composition, structure, and function of climax grasslands.

118. Badlands introduction- Badlands of the Pianted Desert are units of desert scrub found within the larger surrounding desert plains (semidesert) grasslands. Badlands as used in contest of the Colorado Plateau were defined by Chronic (1983, p. 309) as "barren, rough, steeply gullied topography in arid areas with soft sedimentary rocks that contain swelling clays such as bentonite". Painted Desert Badlands were made mostly from erosion of the Chinle Formation which consist of four members including the Petrified Forest Member shown here which is a layered sequence of various red mudstones and brownish sandstones (Geologic Formations, brochure; National Park Service, undated).

Range vegetation of Chinle Badlands was primarily 'nonexistent" ("There weren't no vegetation"), but what plant communities did exist were scrub (= scrubland= shrubland). Principal range plant species in this photograph were sand sagebrush (Artemisia filifolia), littleleaf snakeweed (Gutierrezian microcephala), fourwing saltbush, and Nevada jointfir or Nevada Mormon tea (Ephedra nevadensis). Obviously this shrubland was not semidesert grassland. This example of Painted Desert scrub vegetation was typical of badlands scrub found on this range. It was included to show continuity and diversity of range plant communities within this badlands landscape. In context of Landscape Ecology, Painted Desert (Chinle Formation) Badlands were patches within a matrix of desert plains grassland.

By the way, most of the Painted Desert is actually semidesert grassland and not desert scrub or xeric shrubland, the proper title (name), Painted Desert, notwithstanding.

Petrified Forest National Park, Apache County, Arizona. Mid-July.

Location note: shrublands or scrub types of the Painted Desert Badlands were included in the chapter, Miscellaneous Scrub (Shrublands) of Range Types.

119. Can't git much sparser- A Painted Desert badlands range plant community that was about as simple and sparse as was possible to be: a grass-dwarf shrub savanna of alkali sacaton (Sporobolus airoides) and mound saltbush (Atriplex obovata). Given aridity (eight to nine inches of average annual precipitation) and harsh edaphic nature of this range site which, based on the soil survey (Soil Conservation Service, 1975) was apparently unnamed and not described.

Petrified Forest National Park, Apache County, Arizona. Mid-July.

120. About as much bare as covered- Bunchgrass steppe or, perhaps more precisely, bunchgrass-shrub steppe form of semidesert grassland in the Painted Desert of the Colorado Plateau physiographic province. This range vegetation was a savanna or, perhaps, a semi-savanna in both composition and physiogonomy. All of the major grasses, most of which were of subfamily Eragrostoideae, were cespitose species. There were not dominant or associate grass species other than at local scale. Major grasses were alkali sacaton, Indian ricegrass, needle-and-thread (Stipa comata), blue grama, and red threeawn (Aristida longiseta), Indian ricegrass and needle-and-thread were festucoid (subfamily, Festucoideae) grasses. Galleta and black grama, major grasses on many other ranges and range sites in thie area of semidesert grassland, were only incidental species on this bunchgrass-shrub steppe.

Fouwing saltbush was the major shrub on this range as well as the dominant woody species across much of the Navajo section of the Colorado Plateaut. The second most abundant shrub (actually a subshrub; suffrutescent) on the range shown here was broom snakeweed.

The high proportion of bare ground is a feature characteristic of bunchgrass prairie in many parts of the North American Western Range Region including the Palouse Prairie and Pacific Prairie.

Further views and description of this same range of the bunchgrass-shrub steppe form of semidesert grassland were presented in the following six slide-capiton sets.

Petrified Forest National Park, Apache County, Arizona. Mid-July; early green-up as plants were just coming out of drought dormancy (Extreme Drought, Palmer Index). FRES No. 40. (Desert Grassland Ecosystem). K-47 (Grama-Galleta Steppe). SRM 502 (Grama-Galleta) variant. Brown et al. (1998, p. 40) did not include a desert grassland unit for the Colorado Plateau so closest designation for this semidesert grassland would have to be Warm Temperate Grassland 143, Chihuhuan (Semidesert) Grassland, 143.1, Mixed Grass-Scrub Series 143.14. Loamy Upland range site, eight to twelve inches precipitation..

121. More covered than bare- Semidesert grassland of a savanna form in Painted Desert region (Navajo section) of Colorado Plateau. Dominant was black grama with sideoats grama as the general associate species. Other important grass species were galleta, blue grama, and spike dropseed (Sporobolus contractus) with relative importance (abundance) of these varying at local scale.Alkali sacaton was present as a minor species. The major shrub was fourwing saltbush which had shed leaves (and had not replaced these) due to drought dormancy. There were a few widely scattered plants other shrub species including of broom snakeweed (more properly, a suffrutescent forb), sand sagebrush, common dunebroom (Parryella filifolia), and Nevada Mormon tea. All these woody species together did not have nearly as much cover as fourwing saltbush.

Strictly speading, this grassland savanna was a form of mixed prairie with sideoats grama and spike dropseed being midgrass species in contrast to the other grasses that were shortgrass species. Regardless, this was clearly semidesert or desert plains grassland and mixed or midgrass prairie of the Great Plains. This fact of Plant Geography and the affinity of this semidesert grassland to grasslands of the Great Plains was noted in the florisic sidebar below.

Petrified Forest National Park, Apache County, Arizona. Mid-July; early green-up as plants were just coming out of drought dormancy (Extreme Drought, Palmer Index). FRES No. 40. (Desert Grassland Ecosystem). K-47 (Grama-Galleta Steppe). SRM 502 (Grama-Galleta) generic or in general, but more specifically this example was SRM 703 (Black Grama-Sideoats Grama). Brown et al. (1998, p. 40) did not include a desert grassland unit for the Colorado Plateau so closest designation for this semidesert grassland would have to be Warm Temperate Grassland 143, Chihuhuan (Semidesert) Grassland, 143.1, Grama Grass-Scrub Series 143.11. Loamy Upland range site, eight to twelve inches precipitation..

122. Stand of midgrass- Local consociation or local population (whichever term is more nearly correct) of sideoats grama on bunchgrass-shrub steppe form of semidesert grassland on the Colorado Plateau. Shrubs were fourwing saltbush that had shed leaves or, actually, failed to grow new ones this spring and early summer due to Extreme Drought (Palmer Scale).

The sideoats grama plants seen in this "photoplot" were the strictly cespitose variety, Bouteloua curtipendula cespitosa in contrast to the more common or widespread taxonomic variety , B. curtipendula curtipendula (Barkworth et al., 2003, p. 254). Bouteloua curtipendula cespitosa does sometimes possess short basal rhizomes, but these shoots are "nothing compared to" the long rhizomes of B. curtipendula curtipendula (Gould, 19775, p. 337-339; Barkworth et al., 2003, p. 254).

On this particular range (same pasture as seen in the two slide-caption sets above and the four slide-caption sets immediately below) plants of a single species were often locally dominant to even present to exclusion of othr plant species sop as to exist as local populations or consociations. This "pascel" of sideoats grama was one such exmple of this vegetational feature as was a local population or a stand (whichever term was most appropriate) of needle-and-thread presented two slide-catpion sets below. Thus the vegetation on this range was a mosaic or patchwork of various local--frequently exclusive--populations of one species (single-species stands). This is the nature of cespitose grasses (bunchgrasses) and sod-forming grass species that reproduce primarily asexually by extravaginal shoots (stolons and/or rhizomes). This latter form or pattern of growth and reproduction was shown for the stoloniferous black grama in the next slide, if you please ...

Petrified Forest National Park, Apache County, Arizona. Mid-July; early green-up as plants were just coming out of drought dormancy.

123. Gramagrass and ground- Top-down view of black grama at ground level on a range of the bunchgrass-shrub steppe form of semidesert grassland on the Colorado Plateau. These plants had just initiated new growth for the current warm-growing season, and roughly half an inch of intense rainfall the day before had these "happy" plants "smiling" vigorously. They were in the twelfth year of a horrid, long-lasting drought tin which only one year of the twelve had been decent from a plant-growing standpoint. In absence of heavy grazing these black grama plants had come through in good shape. In fact, this area had been protected from livestock grazing for over a century although almost all species of pre-Columbian wildlife had access to these range plants.

Black grama is a highly stoloniferous and, thereby, a sod-forming species that almost never reproduces sexually (from caryopses). The sod-forming habit is contrast to the bunchgrass growth form of sideoats grama, especially the strictly cespitose variety, Bouteloua curtipendula cespitosa (Gould, 19775, p. 337-339; Barkworth et al., 2003, p. 254) growing on this semidesert grassland range as shown in the immediately preceding "photoplot".

With either the bunchgrass or sod-forming growth form of grasses in this arid (approximately eight to nine inches annual precipitation) region there was limited spatial spread of progeny (short distance of offshoots or clones from parent plants) which resulted in local patches of range vegetation that were often dominated by a single plant species. In this species pattern or structure of vegetation, the range plant community was a patchwork of local populations (or, maybe, consociations) composed primarily of one species.

Petrified Forest National Park, Apache County, Arizona. Mid-July; early green-up as plants were just coming out of drought dormancy.

124. Local congregation- Local population of needle-and-thread on a bunchgrass-shrub steppe form of semidesert grassland on the Colorado Plateau. This local stand of vegetation was on the same range shown in the preceding four slide-caption sets and the two immediately following slide-caption sets. Other range plant species visible in this "photoplot" included sideoats grama, broom snakeweed, and fourwing saltbush.

On this particular range, botanical composition of the range plant community varied locally with first one species and then another species being dominant or, in several instances, almost of exclusive plant cover (ie. present to exclusion of almost all plants of another species). Such locally distinct stands of range vegetation were local consociations or, perhaps, more accurately, local populations. This population of needle-and-thread was one example of such a phenomenon as was that of the stand of sideoats grama seen in the slide-caption set before the immediately preceding set (two sets above).

Petrified Forest National Park, Apache County, Arizona. Mid-July; warn-season dormancy of this cool-season species (shoots were those of the previous winter/spring growing season).

125. Atypical variant- Another range plant community on a semidesert grassland range of the bunchgrass-shrub steppe form (ie. a grass-shrub savanna) on the Colorado Plateau. This range community was on the same range that was featured in the four preceding slide-caption sets. The range vegetation visible in these two landscape-scale views was atypical or, at very least, a less common semidesert grassland community as it was dominated by spike dropseed (Sporobolus contractus). The principal associate species varied among black grama, Indian ricegrass, and sideoats grama. Needle-and-thread was a distant runner-up associate. Blue grama and galleta were present, but they were consisteltly minor species. This was definitely not a blue grama-galleta grassland. The only forb of consequence--and that of minor consequence--was the naturalized, Eurasian, annual chenopod known as Russian thistle or, the generic moniker, common tumbleweed (Salsola pestifer= S. iberica=S. kali tenuifolia).

The dominant shrub was fourwing saltbush (leafless, dull-grey woody shoots) with broom snakeweed (a suffrutescent species), Bigelow's sagebrush, and the succulent subshrub, narrowleaf yucca (Yucca angustissima var. angustissima) being associate woody or, at least, semi-woody plant species. This range was a savanna and boasted a definite savannah physiogonomy, structure, and composition.

Local differences in soil chroma were pronounced in color of land surface between these two "phototransects". Approximately half an inch of rain--and in typical summer fashion of high intensity rainfall for a brief period of time--had fallen on this land late in the preceding afternoon. Range and rangeman were elated. Most of the herbage on this range was necromass (dead plant material) from the previous year as there had been insuffiicient soil moisture for green-up in the current warm-growing season. Dead herbage of needle-and-thread and Indian ricegrass, both cool-season species, had been produced earlier in the current year from marginal winter precipitation.

Petrified Forest National Park, Apache County, Arizona. Mid-July; early green-up as plants were just coming out of drought dormancy (Extreme Drought, Palmer Index). FRES No. 40. (Desert Grassland Ecosystem). K-47 (Grama-Galleta Steppe). SRM 502 (Grama-Galleta) generic or in general, but more specifically this example was a spike dropseed variant SRM 703 (Black Grama-Sideoats Grama). Brown et al. (1998, p. 40) did not include a desert grassland unit for the Colorado Plateau so closest designation for this semidesert grassland would have to be Warm Temperate Grassland 143, Chihuhuan (Semidesert) Grassland, 143.1, Grama Grass-Scrub Series 143.11. Loamy Upland range site, eight to twelve inches precipitation..

126. Atypical lineup- Range plant species on a semidesert grassland of the bunchgrass-shrub steppe form dominated by spike dropseed (Sporobolus contractus). Plant species in this assembly included spike dropseed (all large plants in foreground), Indian ricegrass, Bigelow's sagebrush, and fourwing saltbush (mostly leafless shrubs). This cast of "phytocharacters" were on the same range described in the five preceding slide-caption sets. Dominance by spike dropseed was unusual, dominance by black grama, sideoats grama, needle-and-thread being the typical compositional state of affairs.

Petrified Forest National Park, Apache County, Arizona. Mid-July; early green-up as plants were just coming out of drought dormancy (Extreme Drought, Palmer Index). FRES No. 40. (Desert Grassland Ecosystem). K-47 (Grama-Galleta Steppe). SRM 502 (Grama-Galleta) generic or in general, but more specifically this example was a spike dropseed variant of SRM 703 (Black Grama-Sideoats Grama). Brown et al. (1998, p. 40) did not include a desert grassland unit for the Colorado Plateau so closest designation for this semidesert grassland would have to be Warm Temperate Grassland 143, Chihuhuan (Semidesert) Grassland, 143.1, Grama Grass-Scrub Series 143.11. Loamy Upland range site, eight to twelve inches precipitation..

Sacaton Flats- The following section was devoted to a form (range cover type) of semidesert grassland that consist almost entirely of a single species of grass, alkali sacaton (Sporobolus aeroides), with usually widely scttered shrubs of very few species. This simple-structure, "species-poor" grassland typically developed on land in low-lying areas having nearly level topography. These "flats" as they still called are prone to flooding following heavy rains or even high intensity-short duration showers. Originally (pre-whiteman to early stock-raising frontier) these consociations of alkali sacaton--"sacaton flats", by which they are still known--covered thousands of acres. Even today with considerable land fragmentation and range deterioration there are areas of "sacaton flats" that measure several thousand acres.

"Sacaton flats" historically have comprised some of the most important and productive ranges in parts of southwestern North America. "Sacaton flats" occur as relatively large patches of semidesert grassland in both the Chihuhuan and Sonoran Deserts, but they probably develop into the largest spatial-scale grasslands in western portions of the semiarid zone. In such areas dryland field crop production appeared to be feasible to eternally optimistic farmers. For this reason, many of the original "sacaton flats" were converted to farmland.

Some "sacaton flats" of considerable area still exist Four such ranges of (on) "alkali sacaton flats" were presented in this section. These four ranges were contiguous, but they had received different grazing management--mostly different stocking rates--in the recent past. These three livestock pastures remained consociations of alkali sacaton with most differences among ranges being in utilization (degree of use) which resulted in different cover (basal and foliar; relative and absolute). Most of this difference in cover was due to differences in plant sizes with larger plants growing on ranges that had lighter livestock stocking (lower stocking rates). These four contiguous ranges were in the Little Colorado River Basin (known by knowledgable locals as the Little Colorado River Plateau) in the the more western part of the Painted Desert of the Colorado Plateau physiographic province. The four grazing units were local, low-lying plains known as "red alkali flats" (another local term) in the drainage of the Little Colorado River (Barrs, 1968, ps. 1202) on soils that were of alluvial deposits of the Little Colorado River (Chronic 1983, p. 202). These low-lying ranges had been periodically inundated (and were still just as subject to infrequent inundation) by flash flooding in this basin topography even though they were not in the actual floodplain of the present Little Colorado River. Average annual precipitation of this locale was four to five inches though effective soil moisture was periodically much greater as a result of surface flooding. This was a (perhaps, the) major factor responsible for this rangeland being climax semiceeert grassland instead of desert scrub (= desert shrubland).

Although it is restricted to less xeric sites within its species range alkali sacaton is one of the most widely distributed of the Sporobolus species. Biological range of this lowland eragrostoid grass extends from deep into Mexico northward to extreme south Alberta and British Columbia. Clements (1920, p. 119) listed alkali sacaton as being in the "ten most importnt subclimax dominants" of the North American grassland climax (at formation spatial scale). Alkali sacaton is one of the 200 North American range species that is on the Master Plant List of the International Range Plant Identification Contest sponsored by the Society for Range Management (Stubbendieck et al., 1992. ps. 136-137).

Alkali sacaton is an extremely variable species. Correll and Johnston (1979. 220) reported that in Texas this "very variable" species probably hybridizes and integrades with giant or big sacaton (S. wrightiia). Kearney and Peebles (1960, p. 114) also noted similarity of these two Sporobolus species whose biological ranges (and, likely, ecological niches) overlap.

Powell (2000, p. 193) described forage value of alkali sacaton as Fair for livestock and Poor for wildlife yet concluded it was overall Good forage for ranges on alkaline environments. Stubbendieck et al (1992, p. 137) showed forage value as Fair to good for cattle and horese, Poor for sheep and wildlife even when green, Poor for all grazers when herbage was dead, and Fair as hay when put up prior to or in early flowering. Bottomline folks: alkali sacaton is "as good as it gets" on alkaline or saline range sites in such areas as "sacaton flats". Stockmen have no choice but to use alkali sacaton to best advantage: while plants are still immature, and consistent with stocking rates that permit sustained use of this valuable natural forage resource.

Knowledge source: the following descriptive explanation of the alkali sacaton flats form of semidesert grasssland in the Colorado Plateau was provided to this author by Mr. Stephen (Steve) J. Campbell, Natural Resources/Forestry Specialist. Cooperative Agricultural Extension, University of Arizona. Examples of alkali sacaton-dominated ranges included in this section known to local as "red alkali flats". These are in the general Little Colorado River Basin (or, more precisely, Little Colorado Plateau). The red alkali flats in this area of five inches annual precipitation are subject to infrequent, short-lived, heavy flooding. Clay-based soils of these alkali sacaton flats are high in salts of sodium, potassium, calcium and, to lesser extent, magnesium and extremely low in phosphorus. There is not an O (organic matter) horizon to red alkali soils other than that around the sparse cover of range plants which, again, is limited primarily to cespitose plants (bunchgrasses) of alkali sacaton. Most organic matter that accumulates on the soil surface of these grasslands is carried lower down on the drainage areas by overland flow (surface runoff) of flood water

In regard to species compositon of grassland communities on red alkali flats there are two schools of thought. One (and the more recent) view of semidesert grasslands on alkaline or saline flats in this part of the Colordo Plateau, the Little Colorado River Basin, was that the climax vegetation, the potential natural grassland community, (the natural range prior to overgrazing and other impacts of whiteman and wihiteman-modified Indians) was a composite of alkali sacaton and blue grama and galleta with all three of these as dominants or, even, with alkali sacaton as the chief associate to co-dominant blue grama and galleta. A "more moderate" version of this first view was that blue grama and galleta were associates to the dominant alkali sacaton, but that overgrazing had taken out these more palatable associates.

The other (and much older) interpretation or view of the original or potential natural (climax) vegetation was that even before admitted (obvious) overgrazing, semidesert grasslands on red alkali flats were essentially consociations (to the point of being almost exclusively single-species stands) of alkali sacaton. In this older--the original ecological perspective--these grasslands on the flood water flats were regarded as distinct from upland grasslands co-dominated by blue grama and galleta. There may have been some plants of other grasses (mostly blue grama and galleta) along with some widely scattered shrubs (especially fourwing saltbush), and these may have been greately reduced or eliminated by overgrazing/overbrowsing, but this was a minor impact because any such individuals of these species constituted very small components of the almost exclusively alkali sacaton grassland.

Authors interpretation: The author or this publication subscribed--and strongly so--to the latter, the original, ecological interpretation. Yes, range site descriptions in some soil surveys, as for instance one for the western part of this area (Soil Conservation Service, 1983, ps. 125, 130), included blue grama, galleta, vine mesquite, western wheatgrass, and foutwing saltbush at potential percentages of 12 to 15 percent each so that alkali sacaton comprised no more than 30 to 35 percnet of the climax. Again, the author rejected this interpretation of a more species-rich, more diverse range plant community. (Bio-diiversity as become the "ecologically correct" equivalent of the "political correctness" of diversity and "inclusion".)

The basis for this author's rejection of a grassland mixture version as potential climax vegetation of alkali flats was that the older, more authoritative, and more prevalent literature regarded sacaton flats as just that: grassland communities comprised almost exclusively of (consociations of) alkali sacaton. Clements (1920, p. 17) specified that S. airoides was a dominant "over great saline flats".In its Range plant Handbook Forest Service (1940, p. G109) explained that on its preferred habitat of low-lying, moist alkaline flats, alkali sacaton "... frequently develops in almost pure stands". In fact, on the better sites and when alkali sacaton is not overgrazed "...it may sometimes form a uniform cover approaching a sod". Humphrey (1958) On New Mexico ranges blue grama and galleta were associate species to the dominant alkali sacaton, and alkali sacaton was the species preferred by cattle with blue grama and galleta being "... utilized only after alkali sacaton became scarce" (Hickey and Springfield (1966). This latter observation undermines the school of thought that alkali sacaton dominates red alkaline flats only because blue grama and galleta were grazed out.

Stubbendieck et al. (1992. p. 137) stated tha alkalai sacaton was "most abundant on moderately moist alkaline soils of bottomlands where other sepceis are not adapted". In The Desert Grassland (McClaran and Van Devender (1995. p. 162) reference was made to "alkali sacaton swales, where the clay soils have a high gypsum content". Powell (2000, p. 16) presented a photograph of a nearly pure stand of alkali sacaton on gypseous, saline soil at edge of an ephemeral salt lake in the semidesert grassland in the Basin and Range province of Trans Pecos Texas. A similar photograph of alkali sacaton on a flooded flat, the Lordsburg Playa, in the Basin and Range province in New Mexico was presented in McClarean and Van Devender (1995, p. 91).

On semidesert grasslands in the badlands of the Painted Desert of the Colorado Plateau in northeastern Arizona alkali sacaton is successively replaced by galleta and ultimately by gramas, in particular blue grama (Clements, 1920, p. 282). This is the opposite the pattern of grassland development on highly alkaline flats where alkali sacaton is often the sole or, at least, the overwhelming dominant of as explained in the preceding paragraph. As matter of fact, this sequence of seral development on badlands substantiated the almost sole dominance by alkali sacaton (and absence of blue grama and galleta) on harsher habitats of the highly alkaline frequently flooded flats.

The more upland (and outer margin of or outward from a flat) l alkali sacaton-blue grama-galleta mixed form of semidesert grassland described for this area by the Soil Conservation Service (1983, ps. 125, 130) was presented immediately following treatment of alkali sacaton flats.

One specification, qualifier, or whatever: it was possible that some of the earlier references to alkali sacaton were for (or included) some plants and cover of sacaton, often designated as big or giant sacaton, (S. wrightii= S. airoides var. wrightii). This situation was more likely to have existed in accounts by earlier explorers and stockmen as quoted by Humphrey (1958, ps.16-18) than by later professional and scientific works . In scientifically reliable publications such "lumping" of the two species seemed highly unlikely. The Forest Service (1940, ps, G109, G113) noted in distinguishing between S. airoides and S. wrightii, although this latter species also grows on low, alluvial flats that are subject to flooding S. wrightii "will not grow on soils which are highly impregnated with with alkali". Also, S. wrightii is less drought-tolerant than S. airoides. The absence of S. wrightii from semidesert grassland on nearby Petrified Forest National Park ( ) was consistent with these observations. Clements (1920, ps. 84, 257) cited earlier work showing that S. airoides was the first-named dominant of saline and, especially, alkaline soils. Kearney and Peebles (160, p. 114) distinguished between S. airoides and S. wrightii, but noted that in northern Arizona counties specimens of S. wrightii resembled S. airoides. Powell (2000, ps. 192-194) also noted the similarities as well as distinctiveness of these two species. Barkworth et al. (2003, ps. 126-129 passim) also distinguished between S. airoides and S. wrightii and remarked that S. airoides is "usually assocaited with alkaline soils" whereas S. wrightii grows "near saline habitats".

Thus, these two similar species are generally segregated from each other by salinity and/or alkalinity of edaphic environments. Even so, it remains the case in desert plains (semidesert) grassland that "[i]n alkaline areas, the typical variety of Sporobolus aeroides and S. airoides var. wrightii dominate" (Gould and Shaw, 1983, p. 357). In the minds of most rangemen dominance--especially on semidesert grassland flats--is more than 30 to 35 percent of cover or biomass, Soil Conservation Service (1983, ps.125, 130) range site descriptions not withstanding. Frankly speaking, those SCS percentages that downplay dominance of alkali sacaton on flats or swales seem not to have been based on relict range vegetation or even on hypothetical reconstructions of climax plant communities, but instead on concocted percentages the aim of which was to modify climax blue grama-galleta upland desert plains grasslands by adding a "healthy dose" of alkali sacaton so as to extend a "blended" grama-galleta type onto highly alkaline habitats.

Location note: Semidesert grassland flats on which S. wrightii and S. giganteus was dominants (ie. consociations of sacaton and big or giant sacaton) were shown above under the Chihuhuan Region of semidesert grasslands.

The examples of "red alkali flats" dominated almost exclusively by alkali sacaton (Sprorbolus airoides consociation) were of four contiguous ranges (four adjoining pastures separated by barbed wire fences) that had been in a protracted drought for ten or eleven (depending on criteria used) of the last twelve years. Average annual precipitation in this area is four to five inches, just about as arid as it gets "this side of Death Valley". These four example ranges showed alkali sacaton grasslands under prolonged drought with the following management treatments (as could best be determined by the author): 1) current overuse after recent history of overgrazing (one range), 2) rest and recovery following a history of periodic overuse (two ranges), and 3) long-term nonuse (one range).

These four conterminous ranges were on land subject to periodic flooding with intense rainfall. They were in the Little Colorado River Basin or, perhaps more precisely, Little Colorado River Plateau.of the Colorado Plateau physiographic province. Soil was

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy. FRES No. 40 (Desert Grasslands Ecosystem). Kuchler (1964, in Garrison et al., 1977) did not map units of vegetation at spatial scale of this range cover type. No descriptive biotic community in Brown et al. (1998). No SRM rangeland cover type or variant for alkali sacaton flats. Clay Bottom range site.

127. Resting up- A range that was a consociation of alkali sacaton (and almost nothing else) in the second year of Extreme Drought and that had not been grazed by livestock for several years. This particular range had a prior history of being heavily grazed (heavy use, high degree of utilization), including periodic overuse. In intervening years up to the present time, plants of alkali sacaton had regained vigor with both asexual and sexual reproduction. This was evidenced by both larger plants with much greater foliar and basal cover as well as younger plants which had been seedlings prior to the Extreme Drought and that had survived this severe , natural stress. The basis of comparison for cover, plant vigor (including sexual reproduction) was an adjoining--on-other-side-of-the-fence--range that was presented in the immediately following slide. That next slide please ...

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy. FRES No. 40 (Desert Grasslands Ecosystem). Kuchler (1964, in Garrisonet al., 1977) did not map units of vegetation at spatial scale of this range cover type. No descriptive biotic community in Brown et al. (1998). No SRM rangeland cover type or variant for alkali sacaton flats. Clay Bottom range site.

128. Rode hard and dried out before being put up- Overgrazed range on an alkali sacaton flat (consociation of alkali sacaton) form of semidesert grassland in the Little Colorado River Basin or, perhaps more precisely, Little Colorado River Plateau of the Colorado Plateau physiographic province.Shrubs on this overgrazed range were mostly spiny hopsage (Grayia spinosa) as, for example, gray shrub in slightly right-of-center foreground; Bigelow's sagebrush (Artemisia bigelowi); and, at smaller cover, broom snakeweed (Gutierrezia sarothrae).

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy. FRES No. 40 (Desert Grasslands Ecosystem). Kuchler (1964, in Garrison et al., 1977) did not map units of vegetation at spatial scale of this range cover type. No descriptive biotic community in Brown et al. (1998). No SRM rangeland cover type or variant for alkali sacaton flats. Clay Bottom range site.

Note on color of soil and plants: the three photographs presented immediately above were prior to arrival of a "rolling dust storm" whereas the three photographs shown immediately below were during the by-now-arrived dust storm. All these photographs as well as those of plants and close-in views of this range vegetation were taken within less than half an hour of each other. The "rust" or "reddish-brown" color of the soil in the first three slides and the four slides subsequent slides of plants was the typical chroma of soil these red, alkali flat, clay soils. The seven slides of typical--at least, closer to typical--soil chroma were taken under a light overcast sky that diffused light and did not result in shadows.

All slides (total of ten images) of alkali sacaton on "red alkali flats" had received between a half and one inch of rain 22 hours prior to time of photographs. Chroma of soils was with a still-wet soil surface.

Mr. Stephen (Steve) J. Campbell, Natural Resources/Forestry Specialist. Cooperative Agricultural Extension, University of Arizona.who in persona communication provided much of the basic knowledge and information regarding these "red alkali flats" ranges remarked that this was known as "nasty country". After one short visit to these "sacaton flats" during a summer dust storm your author could attest to the appropriateness of that characteristization.

129. "Grazed proper"- Physiogonomy and species composition of an alkali sacaton flat semidesert grassland that was essentially a consociation of alkali sacaton. This range had been grazed by livestock--mostly or exclusively by cattle, based on presence of dung--within the last year or so. There were a few--with emphasis on few--plants of Whipple's cholla (Opuntia whipplei), the most frequently encountered shrub on this range, spiny hopsage, broom snakeweed, and Bigelow's sagebrush. The author was not privy to the stocking rate of this range, but it was obvious that for several years degree of use had been proper. Stocking rate is alway the single most important factor (management input) in husbandry of any range. This range plant community was on lowland known locally as "red alkali flats".

Viewers were reminded at this juncture that the four ranges being compared had been in drought for ten or eleven (depending on criteria chosen) of the last twelve years. It was Extreme Drought (Palmer Index) at time of these photographs.

It was explained above that this author--based on the classic, long-tern literature--interpreted this as the climax range plant community for this Clay Bottom range site. The potential natural range vegetation is a consociation (single-species stand or, most precisely, a population) of Sporobolus airoides with a few individuals of chenopod and composite shrubs.

The most important unknown fact about this climax semidesert grassland with regard to species composition was what--if any--conponent there might have been of fourwing saltbush (Atriplex canescens). This photographer found no fourwing saltbush on this (or any of the four ranges) that were the subject of this section. Absence of fourwing saltbush from these "red alkali flats" ranges included the one range that had unquestionably been ungrazed by livestock for many years. That was presented in the very next slide...

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy. FRES No. 40 (Desert Grasslands Ecosystem). Kuchler (1964, in Garrison et al., 1977) did not map units of vegetation at spatial scale of this range cover type. No descriptive biotic community in Brown et al. (1998). No SRM rangeland cover type or variant for alkali sacaton flats. Clay Bottom range site.

130. Another one resting up- Physiogonomy and species composition of an alkali sacaton flat semidesert grassland that was a consociation of alkali sacaton with almost no other plant species present. There were very infrequent individuals of spiny hopsage and Bigeglow's sagebrush. The most common shrub on this range from which livestock had been excluded for a very long time was Whipple's cholla which was also the most abundant shrub (although no shrub was abundant on any of these four ranges) on the range presented immediately above that had been properly grazed by livestock, primarily cattle.It struck this author as most interesting that Whipple's cholla cactus was absent from the overgrazed ranges and least uncommon on the range from which livestock had been excluded for years.

Viewers attention was drawn to the meterological fact that this range vegetation had been in drought conditions for ten or, maybe, eleven of the last twelve years. The alkali sacaton on this flat was under Exrtreme Drought (Palmer Scale) at time of this photograph.

It was explained above that this photograph was taken during a local "rolling dust strom" so that the color was modified by that atmospheric condition. (Darker blue sky in distant background belied presence of the local dust storm.) Distant clouds were young cumulonimbus that built up during heat of a warm afternoon, warm enough to spawn winds tht picked up, carried, and re-deposited dust of red clay.

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy. FRES No. 40 (Desert Grasslands Ecosystem). Kuchler (1964, in Garrison et al., 1977) did not map units of vegetation at spatial scale of this range cover type. No descriptive biotic community in Brown et al. (1998). No SRM rangeland cover type or variant for alkali sacaton flats. Clay Bottom range site.

131. Flat from above- A more top-down view of an ungrazed (for quite a few years) climax alkali sacaton flat, a form of semidesert grassland that was a consociation of Sporobolus airoides with very few plants of any other species present. The next "most present" range plant species was Whipple's cholla cactus. There were no plants of blue grama or galleta, two of the most important--often the co-dominant--plant species, in this part of the Painted Desert. There were some plants of Bigelow's sagebrush. Average annual precipitation in this locality was four or five inches, although these "red alkali flats' were infrequently covered for brief periods by flash flood waters in this portion of the Little Colorado River Basin. Such flash flooding, infrequent thought it was, increased soil moisture content appreciatively so that the aridity of four to five inches precipitation was misleading to other than knowledgable rangemen.

This population of alkali sacaton with a few shrubs "thrown in for good measure" was the potential natural vegetation for this Clay Bottom range site. This was a textbook example of an alkali sacaton flat semidesert grassland, a form differing drastically from the grama-galleta upland semidesert grasslands that developed in this same general area of the Colorado Plateau.

The "open" physiogonomy or interrupted canopy, the grass crown cover, of alkali sacaaton flats is a feature determined largely by the cespitose (tufted) habit which in grasses is known generally among rangemen as the bunchgrass growth form (ie. bunchgrasses). Sporobolus species almost never produce lateral or extravaginal shoots (stolons or rhizomes) and instead reproduce asexually by production of vertical or intravaginated shoots known as tillers. So again, plants that consist solely (or almost solely) of tillers have the tufted habit which in the Gramineae are bunchgrasses.

In/on more favorable habitats bunchgrasses may grow so close together that their crowns form a semi-closed herbaceous canopy. In such vegetation the tufted habit of cespitose grasses is less conspicuous and the grassland has less of a bunchgrass prairie or steppe physiogonomy. This more-closed crown cover obviously depends--sooner or later--on establishment and growth of new grass plants (successful recruitment by sexual reprocduction) in the interspeces among established adult plants. Such was exactly the phenomenon that--most conspicuously--had taken place on this long-term ungrazed (or essentially so) range. Numerous smaller (and presumedly younger) plants of alkali sacaton were growing in spaces among larger (and presumedly older, parent) plants. The size/age structure of this population of alkali sacaton attested to sexual regeneration in this strictly cespitose, eragrostoid grass species. Admitttedly there was still much "open ground" within this grass stand, but much less so than in the overutilized and, even, properly grazed (utilized) ranges presented earlier (above in this section).

Comparison among these various grazing treatments (stocking rates and degrees of use) was anecdotal evidence of increased grass reproduction, higher herbage yield, and greater coverage of the soil surface (ie. more soil protection against erosion). The truly spectacular feature of this grass recovery was that the plants seen here had been under the stress of drought for ten or eleven out of the last twelve years with Exrtreme Drought in effect for the last two years. All living things require periodic rest. Long term rest of this alkali sacaton range had "worked wonders".

For whatever reasons, this particular pasture that was "sandwiched" in among three other and livestock-grazed ranges. This range was a default, de facto livstock exclosure. It could be and undoubtedly was grazed by wildlife species. Land ownership in this locality was a checkboard pattern of private, Arizona state, and Navajo reservation land. The owner/administrator of the range shown here had "opted out of the livestock business".

The reddish, red-brown, or rust-colored soil of this "red alkali flat" was noticable in this photograph that was taken before a "rolling dust storm" rolled through (as was the atmospheric condition in the immediately preceding slide) within a matter of minutes of this and the next four slides).

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy. FRES No. 40 (Desert Grasslands Ecosystem). Kuchler (1964, in Garrison et al., 1977) did not map units of vegetation at spatial scale of this range cover type. No descriptive biotic community in Brown et al. (1998). No SRM rangeland cover type or variant for alkali sacaton flats. Clay Bottom range site.

132. Ungrazed plants on a frequently flooded flat- Pair of nested "photo-plots" (second slide was a portion or sub-plot of the first slide) of a consociation of alkali sacaton on a "red alalkali flat" within the Little Colorado River Basin in the Colorado Plateau of northeastern Arizona. This was in the western Painted Desert (Baars, 1968, p. 159; Chronic, 1983, ps. 202).

The characteristic cracked surface of a soil high in clay was apparent in both of these "Photo-quadrants" taken about 22 hours after "showers of blessing" dropped between a quarter an half inch of the "blessed wetness" on this almost-always parched rangeland. Average annual precipitation for this locality is four to five inches, but of coursethese low-lying ranges are subject to periodic inundation by water from flash floods.

These individuals of alkali sacaton were growing on a range that for whatever reasons had not been grazed by livestock for many years. Hence the comparatively large size of these ungrazed cespitose plants. A countervailing factor acting on these grass plants was drought. Drought had plagued this region for ten or--depending on who was doing the counting--eleven of the last twelve years. The last two years had been Extreme Drought (Palmer Index) with almost no precipitation received during the current warm-growing season until the "nice"-- though intense--shower the day before these shots were taken.

The presence of much "open" (bare) soil surface is characteristic of alkali sacaton flats under conditions of extreme aridity as this locality most certainly is even in a non-drought year. Such "openness" in the herbaceous canopy is a feature of bunchgrasses (those having cespitose or tufted habits) in all but the most favorable of environments where indiviual plants of cespitose species grow close enough together as to form a 'sem-sod". Such a physiogonomy generally requires sexual reproduction to produce new plants that can occupy available bare-ground spaces among existing adult plants. Such a condition was shown in the immediately preceding slide.

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy. FRES No. 40 (Desert Grasslands Ecosystem). Kuchler (1964, in Garrison et al., 1977) did not map units of vegetation at spatial scale of this range cover type. No descriptive biotic community in Brown et al. (1998). No SRM rangeland cover type or variant for alkali sacaton flats. Clay Bottom range site.

133. Blessed by microtopography- A small, localized depression on a "red alkali flat" in the Little Colorado River Basin on which alkali sacaton and broom snakeweed grew to extra-large size as compared to plants of these species on the rest of this Clay Bottom range site. There were also some large individuals of spiny hopsage and, fewer yet, of the naturalized, Eurasian, annual chenopod generally called tumbleweed or Russian thistle (Salsola kali var. tenuifolia=S. pestifer= S. iberica, among others). There were no other forbs on this consociation of alkali sacaton.

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy.

134. Where it floods extra-good- A plant of Whipple's cholla on an alkali sacaton flat in a more remote part of the Little Colorado River Basin. This range on "red alkali flat" habitat of semidesert grassland infrequently received extra water via surface runoff due to intense rainfall from summer thunder showers (see two paragraphs below, this caption). Botanical "escorts" to the cactus were mostly plants of alkali sacaton and Russian thistle or common tumbleweed. Whipple's cholla was the most frequent woody plant on "red alkali flats" semidesert grassland dominated by alkali sacaton. Of course, frequency of shrubs on these low-lying grasslands was near zero.

The plant life in this "photo-quadrant" was desecrated by presence of an aluminum beer can which the author in the "heat of a photo-battle" and race against an incoming dust storm failed to see and throw out of the "photo-plot". Presence of this trash by an even trashier human being raised a minor point of photographic ethics. Should the unnatural (= man-made) object be taken out of or, alternatively, left in the photograph to shown the human impact on/ in the natural range vetetation? As Sir Arthur Tansley frequently asked, "Is man part of nature or not?" By way of contrast, there would certainly be no objections if the man-made object had been an arrow head or spear point crafted by Indians. Anyway the beer can served as a guage to show size of this plant of Whipple's cholla.

The reddish color of this clay soil was pronounced following beetween a quarter and half inch of rain less than 24 hours prior to time of photograph.

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy.

135. Just outward from the flats- Alkali sacaton-blue grama-galleta-shrub savanna form of semidesert grassland on western perimeter of Painted Desert. Along with the dominant alkali sacaton and associate species, blue grama and galleta, a woody component of fourwing saltbush, Bigelow's sagebrush, and Navajo yucca (Yucca navajoa) comprised a bunchgrass-shrub savannah type or subtype of desert plains grassland. The shrub in left-of-center foreground of the first slide was a female fourwing saltbush loaded with urticles, the fruit type of this species.

This subtype of the general semidesert grassland (= desert plains grassland) was very similar to the Great Plains-Great Basin transition mixed prairie grassland that was comprised of New Mexico feathergrass (Stipa neomexicana), blue grama, Indian ricegrass (Oryzopsis hymenoides), and galleta along with black greasewood (Sarcobatus vermiculatus) and Bigelow's sagebrush. Both of these rangeland cover types had developed within the Colorado Plateau physiographic province, but they were distinctly different from each other. Aridity was the main distinguished abiotic factor with desert plains olr semidesert grassland being much more arid than the transition mixed prairie. Likewise, botanical composition varied between these two with the dominance by a different midgrass, New Mexico feathergrass, being a major diifferentiating feature.

Climax range vegetation seen here was the alkali sacaton-blue grama-galleta mixed semidesert grassland described for this area by Soil Conservation Service, 1983, ps. 125, 130) which--as was explained above--totally missed (ignored) alkali sacaton flats.

On various upland range sites in both the Chihuhuan and Sonoran Desert Regions semidesert grasslands, which often occur with various desert scrub types in a mosaic or "patchwork" spatial arrangement, are dominated by black grama. Black grama (on uplands) and tobosagrass (on more mesic swales or lowland range sites) are regional co-dominants over most of the semidesert grasslands of the Chihuhuan Region. Blue grama, sideoats grama (Bouteloua curtipendula), and hairy grama (B. hirsuta) are other gramas (grama grasses) that may be locally dominant. Importance of blue grama and galleta as associates in this climax grassland vegetation showed the floristic affinity of the more xeric and westerly semidesert grasslands with the less xeric Great Plains mixed and shortgrass prairies to the east.

In a matter of speaking, the alkali sacaton-blue grama-galleta-shrub savanna type of desert plains (semidesert) grassland was a transition grassland from the alkali sacaton flats treated immediately above and the still yet more xeric, higher, (and certainly better drained) upland grasslands that had more diverse and species-rich climax range plant communities tht were treated immediately below.

These three slides were taken during a light shower and following a thunder storm that delivered between a quarter an half inch of life-giving rain less than two days prior to taking of these photographs. This area had been in drought for ten or, depending on what was considered, eleven of the last twelve years.

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy. FRES No. 40 (Desert Grasslands Ecosystem). K-47 (Grama-Galleta Steppe Desert Grassland Ecosystem). SRM 502 (Grama-Galleta) variant. Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series 142.22 of Brown et al. (1998, p. 40). Sandstone Upland range site.

136. During a light rain- A-first-in-months light rain was falling on range vegetation of an alkali sacaton-blue grama-galleta form or variant of semidesert grassland at far edge of Painted Desert. Range plant species in this "photoquadrant" included alkali sacaton (the largest, cespitose plants), blue grama, galleta, and Bigelow's sagebrush. Note numerous rock fragements on surface of moist soil. This range had gotten between a quarter and half inch of rain less than two days prior to time of this photograph. For ten or, depending on criteria, wleven of the last twelve years.

This "photosample" of semidesert grassland was "nested" (a closer-in view) of the range plant community shown in the three immediately preceding slides.

Coconino County, Arizona. Mid-July; drought (second year of Extreme Drought) dormancy. FRES No. 40 (Desert Grasslands Ecosystem). K-47 (Grama-Galleta Steppe Desert Grassland Ecosystem). SRM 502 (Grama-Galleta) variant. Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series 142.22 of Brown et al. (1998, p. 40). Sandstone Upland range site.

137. Even on uplands- A heavy clay soil on an upland slope in the Painted Desert portion of the Colorado Plateau served as habitat for a desert plains (semidesert) grassland dominated by alkali sacaton with blue grama and black grama as the two associate species. The next two major (next most abundant, greatest cover, density, etc) were sideoats grama and galleta.These two photographs served as "nested photoplots" with the second slide being a closer-in view of the vegetation presented at wide-angle view in the first slide.

This form or variant of semidesert grassland was ecotonal or transition grassland between the low-lying alkali sacaton flats and the more regional or zonal upland grama-galleta grasland. This rangeland had been in drought for ten or, depending on criteria used, eleven of the last twelve years, the last two of which had been Extreme Drought (Palmer Index). These slides were taken about 22 hours after an intense, half-inch intense thunder shower had blessed this locality.

There were absolutely zero forbs and shrubs in this climax range plant community. This natural potential vegetation was steppe physiogonomy of grassland in its "purest form". Steppe (a Russian term) refers to grassland with species of grasses having the strict cespitose (bunchgrass) form; bunchgrass prairie.

Petrified Forest National Park, Navajo County, Arizona. Mid-July; early estival aspect, pre-bloom phenological stage for all plant species which, by and large, were still in drought-dormancy. FRES No. 40 (Desert Grasslands Ecosystem). K-47 (Grama-Galleta Steppe Desert Grassland Ecosystem). SRM 502 (Grama-Galleta) variant. Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series 142.22 of Brown et al. (1998, p. 40). Sandstone Upland range site.

138. Climaxes past and present- Two "photoplots" of climax alkali sacaton-blue grama-black grama semidesert grassland in the Painted Desert of the Colorado Plateau with logs of petrified wood from an extinct (now fossil) species of conifer historically known as Araucarioxylon arizonicum. These views were in Rainbow Forest, Petrified Forest National Park, Arizona. These two at-this-point-in-time "photoquadrants" were snapshots of plant succession and climax vegetations on time scale of aeons (eons). The dominant range plant species in the current climax plant community was alkali sacaton. Other range plant species in this living Painted Desert grassland vegetation included broom snakeweed (Gutierrezia sarothrae), mound saltbush (Atriplex obovata), and fourwing saltbush (A. canescens).

The term eon as used in Earth and Space Sciences such as Geology refers specifically to the period of a billion years, but in general (poetic, perhaps) usage aeon simply means a very long, indefinite period of time. Frederic Edwards Clements was the Einstein equivalent of a theorist-- a grandiose thinker--in plant succession or vegetation development. Clements thought or theorized over the largest temporal and spatial scales. Clements devised an Einstein-like grand classification scheme of development of Earth's vegetation or, same thing, development (and the developmental record) of all vegetation on any particular location on Earth, from the perspective of the planet's geology (Clements, 1916, especially p. 183). He regarded this as a "phylognetic system" of vegetation classification with a series of seres (paths of development) and climaxes (end points of vegetation development; terminations of seres) situated or existing within a longer (bigger temporal scale) sere based on geologic eras. Supposedly (theoretically) Clements' classification "sums up the ontogeny of the climax formation" with phylogenetic relations being found in the geologic past thereby showing "the immediate origins" of current climaxes (Clements, 1916, p. 183)..

Clements' geological, sucessional scheme was founded on the theory of the Geographical Cycle (= later refined to geomorphic cycle, cycle of erosion, geologic cycle) formulated by William Morris Davis, Father of American geography. The geomorphic cycle was to a large degree a function (at least, a partial function) of clikmate. It followed then in Clements' scheme of vegetation development that there was a "correlation of climatic cycles and plant succession (Clements, 1916, p.342), all tied back to geologic development of Earth. Thus, the entire march of all Earth's vegetation was the geosere. Earth's one geosere included both 1) evolution of new species (thereby, new floras) and 2) succession of new climax vegetations (Clements, 1916, p. 346) This Within this one geosere there were four (three that were major) of the next largest or highest units each of which was an eosere. The eosere was a developmental unit, division, or whatever--and actually a pattern or pathway of vegetation development--that occurred during "a vegetation era" ... "of great land vegetation" which was "characterized by the dominance of a distinct population, i.e. pteridophytes, gymnosperms, or angiosperm". "An eosere is the total development [path or pattern of development] of a particular vegetation throughout this period of dominance." The three vegetation eras were Paleophytic, Mesophytic, and Cenophytic which coincided with the three geologic eras of Paleozoic, Mesozic, and Cenosoic. The three eoseres were named after the three vegetation eras that corresponded to the three geologic eras; hence Palosere, Mesosere, and Cenosere or, based on the dominant plant taxonomic form, Pterosere, Gymnosere, and Angiosere, respectively (Clements, 1926, ps. 183, 288-290, 346-347).

Eoseres in turn were subdivided into progressively shorter temporal (and, perhaps, smaller spatial) units: cliseres, coseres, and seres (longest to shortest, respectively). "The clisere is the series of climax formations or zones which follow each other in a particular climatic region in consequence of a distinct change of climate" For example, one climax formation would succeed another (a preceding) climax formation following retreat of glaciers.Within a clisere there "must have been the production of as many climaxes as there were climates". Coseres were defined by seres, each sere being the pathway of vegetation development of one climax within a given climate (ergo, climax was often called climatic climax). Each cosere consisted of two or more seres (Clements, 1916, p. 348). What the geosere and eosere were to each other (their relationship) so were the cosere and sere (ie. their fixed relation) at the smaller, the shorter, scale of the Clementsian scheme of phylogenetic vegetation classification (Clements, 1916, p. 349). Note however:, "No such fixed relationsihp exists between the cosere and clisere, or between the cosere and the eosere. The clisere, on the other hand, is distinctly related to the eosere" (Clements, 1916, p. 349).

It was understandable (at least to this author) why so many plant ecologists, even among Clements' contemporaries-- and not to mention those coming afterward, could not (or did not opt to try to) comprehend Clements' grand scheme. (Much the same could be with regard to Einstein's more elaborate theories.)

Finally, to the matter at hand: a climax past and petrified logs. Petrified columns (albethey now "bucked up" by Mother Nature as "feller") seen on the current grassland climax were the remains of a climax conifer forest of the Mesophytic Era in North America (Clements, 1916, p. 404). Petrified logs lying amid the current climax grassland community of eragrostoid grasses are trunks of Araucarioxylon arizonicum. These trees grew in the Late Triassic Period of the Mesozoic Era which was roughly (very roughly) 250 to 200 million years ago when what is today Arizona was part of the supercontinent of Pangaea. It has been estimated that A. arizonicum grew to heights of 200 feet with diameters up to two feet. Cronquist (1971, p. 414) described Auaucarioxylon species as "among the most primitive modern conifers". Subsequent research suggested that the fossil logs in Petrified Forest National Park actualy belonged to as many as three species so that Araucarioxylon arizonicum was not a bona fide name or species (Savidge, 2007). Such revision is the nature of science (or perhaps it is more the nature of getting scientific publications for tenure and promotion in Academe than for discovering scientific truth). So noted, the comprehensive and detailed study of Savidge (2007) was, even to those who are not wood anatomists, strong evidence against Araucarioxylon arizonicum as the actual species of petrified logs in the Painted Desert. It had long been recognized that there were two other species (Schilderia adamanica, Woodworthia arizonica) of fossilized trees in Petrified Forest National Park., but Araucarioxylon arizonicum (or its rightful species) is still the primary one and the one whose petrified remains were presented here.

The petrified wood of Araucarioxylon arizonicum is known as Rainbow Wood due to the array of colors in some of the more picturesque specimens of this fossilized conifer. Araucarioxylon arizonicum is the State Fossil of Arizona. Definitive reference on A. arizonicum remains that of Ash and Creber (2000) and Ash and Savidge (2004); that of S. adamanica and W. arizonica is Creber and Ash (2004). This fossil wood formed when A. arizonicum trees fell into prehistoric rivers and were later covered by volcanic ash-bearing sediments. As silica from this ash was dissolved and found its way into logs quartz crystals were formed that replaced wood. This is the standard explanation provided by scientists affilitated with the National Park Service for formation of petrified wood in the Chinle Formation of the Painted Desert.

While it has become fashionable among more recent (and perhaps envious) plant ecologists to deprecate or belittle Clementsian theories ("doctrine" or"dogma" according to jealous [Did I say that?] revisionists), none of Clements' detractors have offered anything that comes close to offering an alternative to climatic cycles and climaxes to explain the successional march of vegetation. Some of the "phytoactors" of that grand successional stage were shown in these stills from the production, Climaxes Past and Present.

Petrified Forest National Park, Navajo County, Arizona. Mid-July; early estival aspect, pre-bloom phenological stage for all plant species which, by and large, were still in drought-dormancy. FRES No. 40 (Desert Grasslands Ecosystem). K-47 (Grama-Galleta Steppe Desert Grassland Ecosystem). SRM 502 (Grama-Galleta) variant. Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series 142.22 of Brown et al. (1998, p. 40).

Desert wash- One of the more prominent (though not projecting) landscape features of Desert Climatic Rgions, the Arid Zone, is presence of washes (= dry washes, desert washes).Wash was defined in the American Geologic Institute Glossary of Hydrology (Wilson and Moore, 1998) thusly: "A term applied in the western U.S. (esp. in the arid and semirarid regions of the SW) to the broad, gravelly, normally dry bed of an intermittent stream, often situated at the botton of a canyon; it is occasionally filled by a torrent of water". Likewise, intermittent stream is: "A stream or reach of a stream that flows only at certain times of the year, as when it receives water from springs or from some surface source. The term 'maybe artitrarily restricted' to a stream that flows 'continuously' during periods of at least one month. A stream that does not flow continuously, as when water losses from evaporation or seepage exceed the availaale streamflow" (Wilson and Moore, 1998).

The short section presented below featured two washes in semidesert grassland in the Painted Desert of the Colorado Plateau. The emphasis was on the range vegetation along such washes and not geomorphology of this form of stream. It was not clear to the present author whether or not sides or banks of the channels of washes constituted a riparian zone (hence, riparian vegetation). Along one of the two featured washes it was self-evident that the zone of or immediately adjacent to the wash channel was more mesic than habitats only a short distance outward from the wash channel. Such zonation was not evident along the other wash.

Either way, it was the range plant community of and/or immediately adjacent to the wash channel that was subject of this short section.

139. A wide wash- Jim Camp Wash, an intermittent stream showing channel and adjacent grassland vegetation of giant sandreed (Calamovilfa gigantea), sand sagebrush (Artemisia fiifolia), rubber rabbitbrush (Chrysothamnus viscidiflorus), curlytop gumweed (Grindelia nuda var. nuda= G. squarosa), and broom snakeweed (Gutierrezia sarothrae).

Petrified Forest National Park, Navajo County, Arizona. Mid-July; early estival aspect, pre-bloom phenological stage for all plant species. Range vegetation along margin of wash was: FRES 40 (Desert Grassland Ecosystem). No Kuchler unit. No SRM. Southwestern Interior Strand 253.3 of Warm Temperate Strand 253 of Brown et al. (1998, p. 46).Range vegetation away from influence of wash: FRES 40 (Desert Grassland Ecosystem). K-47 (Grama-Galleta Steppe). SRM 502 (Grama-Galleta). Mixed Bunchgrass-Shrub Series 142.22 of Great Basin Shrub-Grassland 142.2 of Brown et al. (1998, p. 40).

140. Range along a wash- View of range vegetation of a semidesert grassland on and along the channel of Jim Camp Wash in the Painted Desert of the Colorado Plateau (first slide) and on a tributary (at least a drainage) immediately above the wash channel (second slide).

Petrified Forest National Park, Navajo County, Arizona. Mid-July; early estival aspect, pre-bloom phenological stage for all plant species. Range vegetation along margin of wash was: FRES 40 (Desert Grassland Ecosystem). No Kuchler unit. No SRM. Southwestern Interior Strand 253.3 of Warm Temperate Strand 253 of Brown et al. (1998, p. 46).

It could not be determined if the presently existing range vegetation of a giant sandreed-shrub savanna along the bank and immediately adjacent area of Jim Camp Wash was the natural (human-undisturbed based on concept of pre-Columbian state) or if this range plant community was an original giant sandreed consociation of mesic grassland that was in some degree of retrogression characterized by excessive shrub (= brush) cover. Vegetation of Petrified Forest National Park was described (Thomas et al., 2003; Thomas et al., 2009) using rhe relevé method which is essentially that of the Braun-Blanquet Zurich-Montpellier School of Phytosociology (Barbour et al. 1999, ps. 213-217, 238, 241-244, p. 213 for a number of references), a perspective and procedure historically not used by Anglo-American range and forest ecologists. In this author's judgment as a range scientist the relevé procedure is extremely limited in identifying and describing climax or potential natural vegetation as it maps what is there without regard to succession (successional status).

Nonetheless, even with the relevé approach, Thomas et al. (2009, ps. C76-C77) recognized a Calamovilfa gigantea Desert Wash Shrub Herbaceous Vegetation.That was far from settling the matter of the climax potential for this range site because there was mesic semidesert grassland vegetation along washes that were consociations (almost to the point of being single species stands or populations) of giant sandreed. Kindly advance to the next slides please...

141. Two questions- Local "pure" stands (consociations) of giiant sandreed along banks and immediate floodplain (first terrace) of Dry Wash in the Painted Desert of the Colorado Plateau . Soil of this wash was quite muddy from a heavy runoff rain only 20 hours prior to time of photographs. .With possible exception of big sacaton (Sporobolus wrightii) or big or giant dropseed (S. giganteus), giant sandreed is the grass species having largest plants in the semidesert grassland zone that do not grow on permanently inundated (almost-always-wet) soil. Certainly, the reed-sized shoots of giant sandreed exceed those of the Sporobolus species.

Giant sandreed has received almost no study and remarkably little notice in Arizona where these examples of giant sandreed-dominated vegetation occurred. Gould (1951, p. 176) presented a detailed taxonomic treatment of big sandreed in his grass flora of the southwestern United States, there has beeen little since. Understandably, Kearney and Peebles (1960, p. 102) limited treatment primarily to morphological features. Giant sandreed received no coverage in Arizona Range Grasses by either its original author (Humphrey, 1960) or in the updated version (Ruyle, and Yound, 2003). With regard to habitat, Silveus (1933, p. 206) explained that giant sandreed was "plentiful along sandy bankds of streams in northwestern Texas". In addition to sandhills and sand dunes giant sandreed grows on "river banks and flood plains" (Barkworth, 2003, p. 141). Banner et al. (2011, p. 91) also noted that giant sandreed grew on river banks and flood plains in Utah.

Two questions concerning "pure" (single-species) stands or consociations of giant sandreed immediately come to the mind of any desert rat-rangeman: 1) "Is this riparian vegetation?" and 2) "Is this a form of grassland, an herbaceous range plant community comprised exclusively of this one eragrostoid grass species?".The first question actually begs two larger questions. The first of these larger questions is if there is a riparian zone--at all--at low (in fact, almost nonexistent) banks of washes. The second larger question concerns if--and, if so, how far outward from the banks of washes--giant sandreed grows, and grows as a dominant species.

Wash vegetation presented in these two comparatively large "phototransects" was almost exclusively comprised of giant sandreed. Given the highly clonal nature of giant sandreed with its large, rank-growing rhizomes, it was not known where one genetically distinct plant (one genotype) ended and another began. Large clumps or even distinct, seperated-by-space, adjacent clumps could have been one modular genotype. This may be irrelevant. What was clearly relevant--in point of fact, the most relevant aspect--was if the potential natural (climax) vegetation was giant sandreed grassland--interrupted in cover though it was--as seen in these "phototransects" or, alternatively, was the natural vegetation a giant sandreed-shrub community like that shown in the immediately preceding two "phototransects".

If potential range vegetation was a giant sandreed-shrub community (as shown in the preceding "phototransects"), does this potential plant community include as much shrub cover as in the example? Or was the woody cover, as seen above, excessive due to loss of giant sandreed (perhaps through past overgrazing or current non-burning) and consequent increase in shrubs due to range retrogression (ie. does current woody plant covery represent brush invasion)? This area of desert climate was heavily grazed up to roughly a century ago (Thomas et al., 2009, p. 9)

If the potential range vegetation was a giant sandreed grassland (as shown in the two "phototransects" of this current slide-caption set), was the patchy or irregular grass cover at its natural potential? Or was this herbaceous cover of widely spaced clumps of giant sandreed recovering grassland that had been degraded due to past disturbances with possibilities including overgrazing (much or, even, most of the grass cover "grazed out"), fire cessation (even active fire suppression) human traffic (US Route 66 had crossed this general area and Route 66 most likely followed Indian trade routes), or even climate change (maybe even before theoretical human-induced climate change)?

It will always be the case that studies, even observational surveys like this one, raise more questions than they can hope to answer. Such questions do, however, point out things that ultimately must be known for proper range management. Along with these examples of semidesert grassland, questions concerning the very composition, structure and successional status of this range vegetation must be known in order to manage, to plan and direct use of, such native grazing land for its potential.

Petrified Forest National Park, Navajo County, Arizona. Mid-July; early estival aspect, pre-bloom phenological stage for all plant species. Range vegetation along margin of wash was: FRES 40 (Desert Grassland Ecosystem). No Kuchler unit. No SRM. Southwestern Interior Strand 253.3 of Warm Temperate Strand 253 of Brown et al. (1998, p. 46).

142. Typical appearance of a dominant- Characteristic tufted habitat of blue grrama as it grows on semidesert grasslands of the Arizona Colorado Plateau. Blue grama--more specifically some genotypes, ecotypes, etc.--does have short rhizomes, but the species is characteristically a cespitose (tufted) or bunchgrass. Blue grama has a vast species range being recorded from Maine and from Ontario across the Prairie Provinces to British Columbia and south to Mexico then eastward to Florida. The "prime habitat" of blue grama is, of course, the once "endless" grasslands of the Great Plains with mixed prairie and short grass plains being principal among these. The semidesert grassland, driest of all the major grassland associations (Clements, 1920, ps.), are a lesser though nonetheless important "home" for the grass that most rangemen would today (so much of the habitat of little bluestem [Andropogon scoparius= Schizachyrium scoparium] having been literally turned upsidedown) recognize as the single most important range grass in North America. For example, McClaran and Van Devrnder (1995, ps. 54-55) explained that Daubenmire (1978) interpreted the semidesert grassland as being the driest portion (southwest part) of the Bouteloua gracilis Province of the Steppe Region, while specifying that black grama was the arch typical dominant of semidesert grasslands.

The abundance of blue grama in semidesert grassland is--need it be said--a function of its adaptation to dry environments (drought tolerance). On the semiarid "short grass country" of the western Great Plains and Colorado Piedmont blue grama is co-dominant with buffalograss (Buchloe dactyloides), but Weaver and Albertson (1956, ps 33, 104) explicitly explained that blue grama was more drought tolerant than buffalograss. The occcurrence of blue grama as an important associate and, locally, a dominant. species of semidesert grassland while buffalograss is nearly absent from this range type (McClaran and Van Devender (1995, p. 56) attest to this fact of plant adaptation.

Blue grama was naturally included on the 200 species of the Master Plant List for the International Range Plant Identification Contest of the Society for Range Management ((Stubbendieck et al, 1992, p. 82-83). Similarily blue grama was included in the Range Plant Handbook (Forest Service, 1940, p. G29) and in Arizona Range Grasses (Humphrey, 1960, p.27; Ruyle and Young, 2003, ps. 32-33). The latter stated the case well: "Blue grama is probably the best known and the most known Arizona range grass and is one of our most valuable forage plants".

The plants presented here had been in Extraordinary Drought (Palmer Index) and had just started to initiate new shoot growth following recent "showers of blessing". These plants had not been grazed and their foliage was that remaining from the previous spring-summer growing season. By the way, these were good examples of how blue grama "cures on the vine". In absence of conditions conducive to weathering and rotting (warm, wet weather) herbage, especially of the eragrostoid grasses, remains on the range and retains much of the nutrients present in plant tissue prior to dormancy and death of shoot material..

Petrified Forest National Park, Navajo County, Arizona. Mid-July; earliest stages of plant green-up (tiller emergence).

143. Typical flower clusters- Inflorescences of blue grama. The inflorescence type of blue grama traditionally was described as a raceme, one-sided spike or racemose spike (Hitchcock and Chase, 1950, p, 532), or, more recently, panicle of spicate branches (Gould, 1975, p. 336).

Oldham County, Texas. Mid-July; onset of grain-shatter stage..

144. Widely distributed and variable grass- Two plants of red threeawn (Aristida longiseta) the first of which (first slide) was growing on semidesert of desert plains grassland of the grama-galleta type and the second (second slide) on a grama-galleta-winterfat shrub savanna. Both of these were in teh Colorado Plateau physiographhic province. The pronounced differences in habit (sprawling with horizontal shoots versus upright with vertical shoots) between these two specimens exemplified the morphological variability of this widely distributed species. How much of such phenotypic variation is genetically versus environmentally determined is something probably always to be known but by God. Even more along these lines is the question as to how much of the hereditry diffenerces, if any, are genotypic or how many are ecotypic variation. Such morphological differences--be they genetic or merely phenotypic plasticity--are to be expected in a species found over a large geographic area.

Red threeawn is one of the most widespread Aristida species (taxa). It has a species range extending from northern Mexico to British Columbia with specimens having been collected from the Secventeen Western Range States (Gould, 1975, p. 403; McGregior et al, 1986, p. 1139). It was long recognized that several Aristida taxa were so closely related (even just on a morphological basis) as to constitute a taxonomic complex. More recent systematic treatments--even without cladistics--recognized this as the A. purpurea complex including previous species like A. longiseta, A. purpurea, and A. glauca. In the A. purpurea complex several taxa previously regarded as species were treated as taxonomic varieties of A. purpurea (see for eg. McGregor et al. [1986, ps. 1138-1139]). As could be espected, the cladistic-based bunch of Barkworth et al. (2003, ps. 330-335) also employed the A. purpurea complex such that red threeawn was A. purpurea var. longiseta, a treatment used previously in McGregor (1986, p. 1139). In his treatment of southwestern Aristida Gould (1951, ps. 231-245) did not recognize A. longiseta but did include A. purpurea whereas Kearney and Peeples (1961, p. 120) did include A. longiseta as a member of the Arizona Aristida flora although Kearney and Peeples (1961, p. 119) showed--as species-- many members of the current A. purpurea complex as being very similar. In his classic, Arizona Range Grasses Humphrey (1960, p. 16-17) included red threeawn as A. longiseta that was distinct from A. purpurea (Humphrey, 1960, ps. 17-18). In the update version of Arizona Range Grasses Ruyle and Yound (2003, ps. 14-17) made nomenclatural revisions such that these two distinct Aristida taxa became A. purpurea var. longiseta and A. pupuurea var. purpurea consistent with the currently accepted A. purpurea complex. Musical chairs names.

None of the Aristida species (regardless of names) are very palatable, but they are eaten as, in many cases, they are the principal herbaceous species.

First slide: Petrified Forest National Park, Navajo County, Arizona. Mid-July; earliest stages of plant green-up (tiller emergence). Second slide: Bernalillo County, New Mexico. Mid-July; early to middle stage of shoot growth.

145. Big 'un in the sand- Big or giant sandreed (Calamovilfa gigantea) growing on the low bank of a wash in semidesert grassland in the Colorado Plateau. Giant sandreed is clearly the largest, most rank-growing grass of the semidesert grassland of this region. The biological range of big sandreed estends from snd dunes of the Southern High Plains (Kansas, Oklahoma, Nebraska, Colorado, Texas) west to Utah and Arizona. The distribution of this species is another example of the florisitcic affilitation of the semidesert grassland of Basin and Range with the mixed prairie and shortgrass plains of the Great Plains physiographic province.

This huge grass is strongly rhizomatous with long, scaley, creeping rhizomes off of which arise thick, solitary shoots sometimes attaining height heights of six feet (Hitchcock and Chase, 1950, p. 332; Barkworth et al., 2003, ps.141, 143). Tips of inflorescences in specimens presented here were well over seven foot tall. For all its immense size and photogenic habit there has been little study of giant sandreed. In fact, even the habitat of this species has gotten little scientific attention. In The Desert Grassland edited by McClaran and Van Devender (1995) none of the varied authors made mention of either C. gigantea or of wash haabitat and vegetation.

Likewise, even with its giant dimensions and its wide distribution in the interior of the continent, big sandreed produces limited grazable herbage (other than in its narrowly confined habitats of sand dunes and washes) except where it forms extensive and dense colonies. Such conditions sometimes occur and big sandreed may even be harvested as hay or reserved for winter grazing (Leithead et al., 1971, ps. 70-71). Obviously those situations did not obtain in arid environments or along dry washes but by extension, standing herbage of big sandreed would be valuable at critical junctures on desert plains grassland.

Greatest value of giant sandreed--beyond its inherent value as a native species in this natural range ecosystem--was in control of soil erosion and protection of banks of ephemeral streams known as washes or dry washes.

The large green shrubs in background of these two photographs were rubber rabbitbrush.

Dry Wash, Petrified Forest National Park, Navajo County, Arizona. Mid-July; peak vegetative development, panicle expansion stage of phenology.

146. Big bases- Base of shoots of big sandreed. This photograph was taken of plants introduced in the second slide immediately above. Culms of giant sandreed are some of the largest in diameter--"as much as 6mm thick at base" Hitchcock and Chase, 1950, p. 332)-- of any herbaceous grass in North America.

(Dry Wash, Petrified Forest National Park, Navajo County, Arizona. Mid-July; peak vegetative development.

147. Panicles above the sand- Panicles of big or giant sandreed at various sequences of expansion and floret development. These flower clusters were on shoots of the plants presented above.

Dry Wash, Petrified Forest National Park, Navajo County, Arizona. Mid-July; peak vegetative development, panicle expansion stage of phenology.

148. Spikelets on part of a brnch- Spikelets of giant sandreed at pre-anthesis stage along a secondary branch of a large panicle of plants shown above that were growing along a dry wash in semidesert grassland in the Colorado Plateau. There is only one floret per spikelet in the Calamovilfa species (Hitchcock and Chase, 1950, p. 329; Barkworth et al., 2003, p. 140). Giant sandreed produces viable seed inside the grain so that this species reprodeces both sexually as well as asexually or vegetatively (Leithead et al., 1971, p.71).

Dry Wash, Petrified Forest National Park, Navajo County, Arizona. Mid-July; peak vegetative development, panicle expansion (pre-anthesis) stage of phenology.

149. Showy one of a showy forb family- Wyonming Indian paintbrush (Castilleja linariaefolia) growing on outter bank of a wash through semidesrt grassland in the Colorado Plateau of northeast Arizona. Castilleja species are showy and numerous. Kearney and Peebles (1960, ps, 787-790) provided a key to and described 13 Castilleja species. These species range in general size and, more specifically, in height from short and comparatively small to medium-large by forb standards. The specimen seen here exceeded five feet in height. It was slightly woody at base or, as stated by kearney and Peebles (1960, p. 787), "barely suffrutescent".

This individual plant was a neighbor to giant sandreed (see immediately above) in the herbaceous range plant community of a wash that was dry most of the year.That habitat may partly explain the large size of this grassland forb. Frequently Castilleja species are parasites on roots of neighboring plants (Hermann, 1966, p. 261; Diggs et al., 1999, p. 996).

On particularily interesting feture about Indian paintbrush species is that the bracts (these are typically conspicuously red, orange, or less commonly, yellow in color) that subtend the flowers are showier than the petals (Kearney and Peebles, 1960, p. 787; Hermann, 1966, p. 261; Diggs et al., 1999, p. 996). This characteristic was visible in this photograph and even more so in the next two slides.

Dry Wash, Petrified Forest National Park, Navajo County, Arizona. Mid-July; peak-bloom phenological stage.

150. Bloomin' for you- Individual flowers of Wyoming paintbrush growing in the herbaceous range community that developed along a wash which was dry most of the time. Diggs et al. (1999, p. 996) described the inflorescences of Castilleja species as "leafy-bracted spikes" with inconspicuous corollas (petals) and, as explained in the immediately preceding cption, the bright coloration of "flowers" being due to the subtending floral bracts. Hermann (1966, p. 261) described Castilleja flower clusers as consisting of of "very irregular flowers" "... borne in conspicuously bracted terminal spikes".

Kearney and Peebles (1960, p. 787) noted that the flowers of C. linariaefolia were eaten by Hopi Indians.According to Hermann (1966. p. 263) Castilleja linariaefolia is an important forage plant, at least in some local areas. Perhaps the most useful attribute of C. linariaefolia today is for "PR" (public relations) or promotion and publicity: it is the State Flower of Wyoming. Salute to the Equality State from the Grand Canyon or Copper State.

Dry Wash, Petrified Forest National Park, Navajo County, Arizona. Mid-July; peak flower development.

151. Big and showy in a dry country- Desert-mallow, apricot-mallow or desert globemallow (Sphaeralcea ambigua) growing on semidesert grassland (first slide) and on Rocky Mountain juniper (Juniperus scopulorum)-dominated bunchgrass-woodland (more of a savanna) in the Colorado Plateau. Kearney and Peebles (1960, p. 543) remarked that apricot globemallow is the most xerophytic species (out of a total of 16 species) of Spaeralcea in Arizona. The current author observed that it also a species well-adapted to a wide array of habitats (albeit all of them xeric environments) ranging from lower ponderosa pine forest to semidesert grassland to desert scrub.

S. ambigua is best described as being suffrutescent ("slightly woody toward base, barely shrubby" ) to sufruticose ("somewhat or slightly shrubby") in that plants have a woody base from which arise numerous (up to 100 or more) shoots many bearing large inflorescences with some of the largest flowers of any Sphaeralcea species (Kearney and Peeples, 1960, ps. 543, 1004). An example of this impressive flower cluster was presented immediately below. Add to the notable morphology of this species its broad distribution in varied dry habitats and it is a "damned impressive" range forb. And by the way, both of the specimens presented here had made their growth under prolonged Extreme to Exceptional Drought (Palmer Index).

Palatability of this species to range animals was not known to this author.

First slide: Petrified Forest National Park, Coconino County, Arizona Mid-July ; early bloom phenological stage. Second slide: Cibola County, New Mexico, Late July; peak-bloom phenological stage.

152. Showy single rack- Spectacular flower cluster of desert or apricot globmallow produced on a Rocky Mountain juniper-bunchgrass savanna or woodland in the Colorado Plateau and, incidentially, under conditions of Extreme to Exceptional Drought (Palmer Scale). This inflorescence was a thyrse or thyrsoid panicle, "a more or less contracted panicle with the main axis indeterminate and the ultimate flower clusters cymose" (KIearney and Peebles, 1960, ps. 543, 1004). The adjective "apricot" apparently was in reference to the color of petals which vary from mauve- through apricot- to grenadine-coloration (Kearney and Peebles, 1960, p. 543).

This inflorescence was one of several growing on the specimen presented in the second slide in the preceding slide-caption set.

Cibola County, New Mexico. Late July; peak-bloom stage..

153. James at wild- James wild-buckwheat (Eriogonum jamesii var. flavescens) at edge of unique local shrubland within semidesert grassland on the Colorado Plateau in northeastern Arizona. This was one of several Eriogonum species mentioned briefly by Hermnann (1966, p.69) who dispensed with it noting it was "[a]lmost negligible as a forage plant".

Petrified Forest National Park, Navajo County, Arizona. Mid-July; immediate pre-bloom stage of phenology.

154. Shoot, James- Details of James wild-buckwheat showing most of shoot including immediate pre-bloom inflorescence (first slide) and lower shoot with characteristic leaves (second slide) growing on a unique, local shrubland in a large expanse of semidesert grassland.

Petrified Forest National Park, Navajo County, Arizona. Mid-July; immediate pre-bloom stage of phenology.

156. "Nephrophyllus" forb- Kidney-leaf wild-buckwheat (Eriogonum subreniforme) on semidesert grassland represented by base of plant where most leaves are clustered (first slide) and small flowers on secondary branches of the panicle (second slide). This plant was growing on a locally disturbed microsite with Russian thistle (Salsola kali-tenuifolia) as its closest neighbor.

Apparently there is not much more knowledge about this little wild-buckwheat than there is forage to it. A range forb with some neat morphological features. Put this old Range Management professor in mind of some most of his students: nearly worthless (more common) but sort of "cute" (less common).

Navajo County, Arizona. Mid-July; immediate pre-bloom stage of phenology.

157. In her natural prime- Large, robust female plant of fourwing saltbush (Atriplex canescens). This valuable browse plant of the Chenopodiaceae (goosefoot or saltbush family)was characteristically the dominant woody species on grama-galleta semidesert grassland in the lower Colorado Plateau. This handsome specimen was growing in a more eastern part of the Colorado Plateau.

The value of this shrub as an extremely important and widespread browse plant was attested to by its inclusion in such references as Dayton (1931, pp.28-30), Forest Service (1940, p. B27), Vines (1960, pp 236-237), Sampson and Jesperson (1963, pp.64-65), Lamb (1989, p. 54), and Francis (2004, pp. 93-95). Fourwing saltbush is the most widely distributed Atriplex species in North Amreica. Its palatability varies among browsing species as well as seasonally (Sampson and Jesperson (1963, p.65), but it is regarded by knowledgable rangemen as an extrmely important browse plant across its biological range.It is one of the most commonly reseeded of all woody range plants in North America.

Torrence County, New Mexico. Mid-July.

158. Urticles of fourwing saltbush- Young and still small fruits (urticles or nutlets) and older, nearly full-grown urticles of fourwing saltbush (first and second slides, respectively) of fourwing satlbush on semidesert grassland in the lower Colorado Plateau. The wings (four per fruit) on this fruit are extended or elongated bracts there being four wings per fruit with fruits arranged in axillary spikes (Diggs et al., 1999).

Dayton (1950) defined urticle as "a small, bladderlike, indehiscent, one-celled, usually one-seeded fruit with a thin, membranous covering (pericarp) as fruits of the goosefoot family, Chenopodiaceae".

Navajo County, Arizona. Mid-July.

159. Boys' day out- Two large specimens of male plants of mound saltbush, broadscale, or broadscale saltbush (Atriplex obovata= A. jonesii) growing on dry, harsh microsites in grama-galleta semidesert grassland of the lower Colorado Plateau. All Atriplex species are dioecious. Broadscale was not nearly as abundant as fourwing saltbush on semidesert grassland ranges in this region. Broadscale or mound saltbush was more restricted to gravelly, shallow--in short, more extreme or less favorable--habitats.

Apache County, Arizona. Mid-July.

160. A guy thing- Blooming leaders of male mound saltbush or broadscale (first slide) and staminate flowers at immediate pre-anthesis on this same specimen (second slide). Male flowers of the Atriplex species are borne in globules or globular-like organs. This plant was growing on an ungrazed range of grama-galleta semidesert grassland in the lower Colorado Plateau. Inmage captured in early morning light.

Apache County, Arizona. Mid-July.

161. Gals' turn- Two female plants of mound saltbush that set up housekeeping on an extremely xeric, shallow microenvironment in the lower Colorado Plateau. The second of these two slides presented an up-closer view of the larger sister of the duo in the first slide. The microhabitat featured here was badlands in what has historically been called the Painted Desert which, except for badlands, is strictly speaking semidesert grassland and not desert scrub, the poetic designation notwithstanding.

Petrified Forest National Park, Coconino County, Arizona. Mid-July.

162. A girl thing- Leader on a female plant of mound saltbush or broadscale showing pistillate spikes and some young fruits. Both staminate and pistillate flowers of this dioecious species are borne in a spike inflorescence (Vines, 1960, 240-241). Spikes of both sexes resemble each other (at least from some distance) in earlier stages of floral development.

Petrified Forest National Park, Coconino County, Arizona. Mid-July.

163. The common cactus of sacaton flats- Three views of Whipple cholla (Opuntia whipplei). There were some soon-to-open flowers along with berries (the fruit type in cactus is a berry) in the first two slides while the third slide showed immature fruit. Whipple cholla is a common associate of alkali sacaton in this portion of the Colorado Plateau. The cholla species of Opuntia are in subgenus, Cylindroopuntia.

Navajo County, Arizona, Mid-July.

164. A joint operation- Local colony of Nevada joint fir or Nevada Mormon tea (Ephedra nevadaensis) on a blue grama-galleta dominated semidesert grassland in the southern Colorado Plateau. The first of these two slides presented a portion of that colony while the second slide offered a view into the interior of this group of shoots. E. nevadensis commonly grows "...in large pure stands..." comprised of plants with "... an expanded root crown..." (Francis, 2004, p. 307). Hence the expansive colonies frequently seen in southwestern deserts and semidesert grasslands. Almost all descriptions of Ephedra made reference to the "much-branched" habit or morphology of this group or of individual species.

Ephedra is the sole genus of Ephedraceae, the Mormon tea or jointfir family, and, for that matter, the order of Ephedrales. Some of the older botanical treatments such as Colter (1891-1894; ps. 552-553), Tidestrom (1925, p. 56) and Dayton (1931, p. 12) included Ephedra in the expanded family, Gnetaceae. Nevada jointfir is one of the shorter-shooted Ephedra species. All Ephedra species are dioecious. As there were no cones on the specimen shown here its sex was unknown to the author.

Bureau of Land Management, Coconino County, Arizona. Mid-July.

165. Joined joints- Two views of shoots of Nevada jointfir or Nevada Mormon tea on blue grama-black grama-galleta semidesert grassland on the southern Colorado Plateau. Basis of the common name of jointfir (sometimes joint-pine) was obvious in these two slides.

One good reference, complete with line drawings, for Ephedra species of the southwestern deserts was McMinn (1939, ps. 44-48) although this work did not offer a good description of vegetative features of the species nor did descriptions in Shreve and Wiggins (1964, ps. 224-226). Dayton (1931, ps. 12-13) and Vines (1960, p. 38) also gave apt descriptions along with line drawings. One of the best recent treatments was Francis (2004, ps. 307-309) who concluded that Nevada Mormon tea furnished browse and cover for wildlife, at least during winter and drought. As was typical of the older literature, Dayton (1931, p. 12) specified that Nevada jointrir provided browse for domestic ruminants on winter range with its palatability to cattle in winter approaching 40% (whatever that meant in the range vernacular of a more practical time).

First slide: Bureau of Land Management, Coconino County, Arizona. Mid-July. Second slide: Petrified Forest National Park, Navajo County, Arizona.

166. Subshrub sweethearts- Two plants--female (L.) and male (R.)--of winterfat (Eurotia lanata) on a plains-mesa grassland subshrub savanna (with winterfat being the dominant shrub) in the Colorado Plateau. Winterfat is a dioecious species. In this slide the plant on left was a female and the plant to the right was male. The dominant grass on this semiarid zone range was blue grama but there were certain range sites on which blue grama and galleta were codominant.

Winterfat is one of the more important and widely distributed woody or semiwoody plants through the more xeric portions of the Western Range Region having a species range from deep into Mexico north to the Canadian Yyukon and including parts of the Prairie Provinces and the Seventeen Western Range States. Winterfat is limited to western portions of the eastern Plains States (Texas through North Dakota) so that its primary distribution is in semiarid and arid precipitation zones.

Winterfat has been described variously as a half-shrub, undershrub, sub-shrub, semi-shrubby plant or by such taxonomic terms as suffrutescent or suffruticose. These latter two adjectives mean literally "becoming undershrubby" and "true undershrubby", respectively". In a continuum of descriptive terms ranging from herbaceous through frutescent ("somewhat shrubby", "becoming a shrub") to fruticose ("shrubby, " a true shrub") winterfat is somewhat toward the lesser array of "woody" categories. Perhaps the most descriptive term for winterfat is subshrub, a noun used by botanists as for example by Vines (1960, p. 1032) who defined subshrub as meaning a "perennial plant with lower portions of stems woody and persisten". Apparently Francis (2004) in the more recent descriptions of United States and Territories did not feel that winterfat was close enough to a shrub to be included.

Good treatments of winterfat as a range plant--sub-shrub, half-shrub, undershrub, semi-shrub, or whatever--were found in "all the usual suspects" including Dayton (1931, ps. 31-33), Forest Service (1940, B76), Vines (1960, p. 242), and Lamb (1989, p. 55). And, of course, winterfat has always been on the Society for Range Management list of 200 species master list for the International Range Plant Identification Contest (Hatch et al., 1992, pp. 306-307). Obviously, winterfat was included in all the floras or manuals of states, privinces, or regions in which it is part of the flora. Some of these included some of the recent synonyms for the genus Eurotia, names this traditionalist author saw fit not to dignify.

Torrance County, New Mexico. Mid-July.

167. Fat boy- Male plant of winterfat on a plains-mesa grassland subshrub (winterfat being the dominant woody to semi-woody plant) savanna in the Colorado Plateau. This was the male plant introduced in the preceding slide. Flowers on this plant were in immediate pre-anthesis stage with staminate flowers near the stage of opening.

Torrance County, New Mexico. Mid-July.

170. Fat girl with plump limbs- Female plant of winterfat in "full fruit" (peak fruit stage) on a semidesert grassland subshrub savanna. (Winterfat was the dominant subshrub or semiwoody plant on this range.). Blue grama was the dominant grass with galleta the associate or, sometimes, co=dominant grass.

Bureau of Land Management allotment, Bernalillo County, New Mexico.

171. Fuzzy fruits on fat girl- Fruit-bearing leader (first photograph) and close-in view of fruits (second photograph) on a female plant of winterfat (as with most members of the Chenopodiaceae winterfat is a dioecious species). Fruit type of winterfat is winged indehiscent nutlet.

Bureau of Land Management allotment, Bernalillo County, New Mexico.

172. Rubbery, roughed-up, and ragged - Rubber rabbitbrush (Chrysothamnus nauseosus) on grama-galleta semidesert grassland. Rubber rabbitbrush is a widely distributed woody species across much of the semiarid and arid parts of the Western Range. This specimen was growing on a more xeric habitat and, as typical of plants growing on less favorable environments, it had generally sparser foliage and a higher proportion of dead to live leaders. Plants of rubber rabbitbrush growing on more mesic environments such as those on plains-mesa grasslands and pinyon pine-juniper woodlands are usually more robust and foliaceous. Examples of such more vigerous specimens were presented in the chapter, Juniper-Pinyon Woodland.

Petrified Forest National Park, Coconino County, Arizona. Mid-July.

173. Jimmied-up- Jimmyweed, jimmy goldenweed, or, sometimes, rayless goldenrod (Isocoma heterophylla= I. wrightii= I. pluriflora= Haplopappus pluriflorus= H. heterophyllus= Aploppus heterophyllus) growing on a small sacrifice area on blue grama-black grama-galleta semidesert grassland in the lower Colorado Plateau. The second of these two photographs presented sexual (blooming) leaders showing details of leaves and inflorescences. Jimmyweed is a subshrub (Powell, 1988, p. 445) or, using taxonomic adjectives, suffrutescent or suffruticose. Hiowever, Vines (1960, p. 1004) included this perennial, that he described as being "woody toward the base", in his classic, Trees, Shrubs, and Wooldy Vines.

Jimmyweed is indicative of overgrazed ranges which is, of course, generally indicative of low palatability (Kearney and Peebles (1960, p. 862). In spite of its unpalatability, jimmyweed can be a highly toxic range plant causing the disease known generally as "milk-sickness" or "milk-sick" (Kingsbury, 1964, 408-409; Schmutz et al., 1968, ps. 42-43; Burrows and Tyrl, 2001, ps. 181-183; The poisonous principle (toxin) in jimmyweed appears to be tremetol which interfers with metabolism including the tricarboxylic acid cycle ( Burrows and Tyrl, 2001, p. 182). The closely related burrow weed (Isocoma tenuisecta= Haploppapus tenuisectus= Aplopappus tenuisectus), which is a true shrub (and another invader on overgrazied ranges), also causes the "tremers", "akali sickness" or milk-sickness" (Kingsbury, 1964; ps. 408-409; Schmutz et al., 1968, ps. 44-45; Francis, 2004 p. 389)

Navajo County, Arizona.. Mid-July; peak bloom stage of phenology.

175. Jimmied fruits- Flowers in various stages of maturity along with clusters of achenes (fruit type of composites) of jimmyweed, jimmy goldenweed, or rayless goldenrod.

Navajo County, Arizona.. Mid-July.

176. Threaded and snakey- Threadleaf snakeweed, small-headed matchweed, or stick snakeweed (Gutierrezia microcephala) on a locally disturbed habitat that was ecotonal between blue grama-black grama-galleta semidesert grassland and a unique mixed shrub scrub in the so-called Painted Desert. Threadleaf snakeweed can be a poisonous plant. The toxic principle(s) has not been conclusively identified although there are several suspect compounds including saponins and monoterpenes; symptoms vary but often include abortion and/or liver and kidney damage (Kingsbury, 1964, ps. 406-408; Schmutz et al., 1968, ps. 40-41; Burrows and Tyrl, 2001, ps. 169-170).

Petrified Forest National Park, Navajo County, Arizona.. Mid-July; peak bloom stage (at least on part of the plant crown).

It was noted in the introduction to semidesert grasslands that relatively few students of rangelands, native vegetation, etc. have realized (or recognized) that there are semidesert grasslands in the Great Basin. For example, neither Schmutz et al. (in Coupland, 1992, pgs. 337-362) nor McClaran and Van Devender (1995) in the two closest to comprehensive treatments of semidesert grasslands so much as acknowledged (let alone described) Great Basin desert grasslands. Such native semidesert grasslands do indeed exist (see below).

Intuitively this omission would appear to be a result of the rather restricted distribution-- hence limited economic and cultural importance-- of this generally arid grassland(s) with its various cover types or subtypes. As a indicator of this Welsh et a. (1993, p.7) in A Utah Flora commented: "Grasslands, those areas dominated mainly by grass species, occur widely in the state, but the total area occupied by them, when compared to that dominated by woody and herbaceous species together, is not large". These workers then described plant communities including various desert scub, chaparral, pinyon-juniper woodland, forests, alpine, and even hanging gardens but no grassland! (Obviously grasslands occupy far greater "total area" and are of more survival importance to man than hanging gardens.) Similarly (and perhaps setting a precident) in the classic Flora of Utah and Nevada Shantz (in Tidestrom, 1925. 15) did not include grasslands as plant communities other than as "alpine grassland", which strictly speaking is not grassland. In a description of the natural vegetation of Nevada Tueller (1975, p. 24) observed: "Within the Great Basin there are few natural grasslands, i.e., stands of vegetation that have no overstory of shrubs and/or trees and only a few forbs intermingled". Tueller (1975, p. 25) provided very short but poigant descriptions of some of these natural grasslands. Tueller's comments on Nevada grasslands were used to good advantage in some of the following presentations of Great Basin semidesert grasslands.

A major problem from standpoint of natural vegetation classifiction and rational organization for treatment of range cover types is whether to interpret certain native plant communities as grassland, shrubland (ie. Great Basin desertscrub), shrub steppe, or a shrub savanna. In regards some kinds of range vegetation consisting of shrubs and grass there is a continuum from what is obviously grassland with but very sparse cover or limited density (say, trace amounts) of woody plants to desert scrubland with little or no herbaceous species (including grasses). A textbook example of this phenomenon involves Palouse Prairie cespitose grassland, sagebrush (Artemisia spp.) shrub steppe, and sagebrush desert with little understorey. This array exists mostly to the north of the Great Basin. However, parallel conditions do exist widely in the Great Basin with the sagebrush- and saltbush/greasewood (Atriplex/Sarcobatus)-defined communities as well as those natural plant communities involving such shrubs as Mormon tea or jointfir (Ephedra spp.). Range plant communities that pose the real problems in this regard are not those dominated by these shrub species because they are obviously arid shrublands (= deserts). Nor is there much problem with recognized shrub steppe like the sagebrush-bunchgrass steppe that occurs in northern portions of the Great Basin. This latter range vegetation was logically placed in its singular category of savanna-like grassland. It was treated as such in this publication. Students of Great Basin vegetation have traditionally distinguished between sagebrush shrub steppe and Great Basin sagebrush desert (eg. West in Barbour and Billings, 1988, p. 212-217).

The "tough calls" are those range types that fall between what is obviously grassland and shrub steppe (a shrub-grass savanna). To a lesser degree this condition also applies to Chihuhuan and Sonoran semidesert grasslands. For example, large individual plants-- and at different densities and cover-- of Ephedra and Yucca species are part of the virgin grassland vegetation. It was noted above, that Dick-Peddie (1993, p.116) used longleaf Mormon tea or longleaf jointfir (Ephedra trifurca) as a "diagnostic (climax) member of Desert Grassland". A similar and, probably, homologous phenomenon obtains in Great Basin vegetation with Nevada Mormon tea or Nevada jointfir (E. nevadaensis) and grasses like Indian ricegrass (Oryzopsis hymenoides= Stipa hymenoides), galleta (Hilaria jamesii), and needle-and-thread (Stipa comata). The ubiquous presence of Nevada jointfir and widespread dominance of galleta when compared to the same phytoecological conditions of Ephedra and tobosagrass (Hilaria mutica) demonstrated beyond doubt to this author the homology and ecological affinity or relatedness of Great Basin semidesert grasslands to those of the Chihuhuan semidesert grassland ranges.

This perspective was apparently not shared by those in the Nevada Natural Heritage Program (2003) who recognized a Nevada jointfir/Indian ricegrass community as shrubland and not grassland. There again, the National Vegetation Classification for Nevada (Nevada Natural Heritage Program, 2003) did not ever use the designation of grassland even for what are obviously grasslands but instead applied the title of "herbaceous alliance" or "herbaceous vegetation". Likewise, Brown et al. (1998, p. 40) recognized a Chihuhuan semidesert grassland, but they did not recognize a Great Basin semidesert grassland and instead designated this range vegetation as Great Basin Shrub-Grassland (142.2) within Cold Temperate Grassland (142.). West (in West, 1983, p. 415) described one of the semidesert grassland range cover types given below and remarked that "... the type is locally known as 'semi-desert grassland'". "This rangeman author knows grassland when he sees it. The reader of this publication can decide for himself, but please view the range vegetation first.

.Great Basin grasslands existing as prairie or steppe in foothills and mountains, meadows (including those dominated by grasslike plants such as wet or flood meadows), alpine (eg. alpine turf), and riparian zones (eg. Elymus cinerus, basin wildrye, stands) are not semiarid grasslands, even though they occur within the arid zone or desert climate. With such exceptional range vegetation local habitats and marid ecological factors (eg. edaphic, topographic, fluvial features) override regional climate. Therefore, these grassland range types were not included in this chapter but rather in those that were a "better fit" (eg. Great Basin sagebrush shrub steppe was included in that chapter, wet meadows or grass/grasslike plant-dominated riparian vegetation in the meadows chapter).

Some examples of Great Basin range types that naturally fell into a "gray zone" and could arbitrarily be interpreted variously as either shrub steppe, grass-shrub savanna, or natural grassland widely scattered diagnostic (climax) shrubs were included in several chapters. For example, two rangeland types with swards (more-or-less continuous herbaceous cover) of needle-and-thread (Stipa comata) and Indian ricegrass with well-dispersed Nevada jointfir could logically be viewed as either semidesert grassland, bunchgrass shrub steppe, or less xeric forms of Great Basin Desert (arid or, maybe, semiarid shrubland). These two range types that were obviously--at least to this rangeman photographer-- climax vegetation were placed in both the semidesert grassland and the shrub steppe chapters herein with explanatory notes.

Given the arbitrary categorization of some kinds of climax range vegetation in which substantial cover of woody plants (eg. natural communities dominated by grasses but having conspicuous and greater-than-scattered cover of shrubs like Ephedra, Artemisia, or Chrysothamnus species) some examples of range types were included under both semidesert grassland and Great Basin Desert designations (in both of these chapters). This was done for convenience of readers and to acknowledge the uncertain interpretation of climax range plant communities that apparently have shared dominance by grass and shrub species (at least aspect dominance in regards to shrub cover).

177. Grassland at its grandest grandure- Probably the ultimate expression of Great Basin semidesert grassland is the Indian ricegrass rangeland cover type which is a consociation of this festucoid grass species. (This range resembled a seeded monoculture pasture as much as what was essentially a natural single-species stand.) The grassland range vegetation presented here was not only virgin it was pristine ("mint condition"), and it had been grazed by cattle as part of a Bureau of Land Management allotment! As was shown in these photographs, Indian ricegrass grassland often has Douglas or viscid rabbitbrush (Chrysothamnus viscidflorus) as the major associate shrub species with widely scattered individuals of winterfat (Eurotia lanata= Ceretoides lanata). Total cover and density of woody plants was negligible however. Noone knowledgable of natural vegetation would doubt that this was semidesert grassland in its "purest" textbook expression. Nor would any with a shread of a rangeman's soul doubt the beauty of this magnificant grassland range ecosystem and landscape.

Tueller (1975, ps. 23-24) remarked that one of the few types of natural grassland in Nevada were those consisting of "pure stands of Oryzopsis hymenoides" that developed at edges of salt desert scrub in low-lying areas. Unfortunately (and erroneously based on this author-photographer's experience and the observation of Tueller [1975, p. 25]) this climax range plant community was not listed in either the Preliminary Vegetation Classification for Utah and Nevada (Bourgeron et al., 1994) or the National Vegetation Classification for Nevada (Nevada Natural Heritage Program, 2003) but Association for Biodiversity Information (2001), which included nevada and Utah, named an Achnatherum hymenoides Herbaceous Alliance. (Apparently "herbaceous alliance" meant grassland.) The Society for Range Management (Shiflet, 1994) did not offer a name and description for an Indian Ricegrass cover type for the Great Basin.

The largest space opf bare soil in the first (upper) of these two photographs (right-center foreground) was entrance to den of Ord's kangaroo rat (Dipodomys ordii), the dominant and defining animal of this and some related Great Basin scrubland communities (see the Great Basin Salt Desert Shrubland portion of the Great Basin Desert chapter herein).

Bureau of Land Management, Fillmore Field Office, Millard County, Utah. June (early estival aspect; phenology from soft-dough to grain-ripe stage). FRES No. 40 (Desert Grasslands Grassland Ecosystem). No Kuchler designation for the climax grassland of this spatial scale. No SRM. No association-level designation by Brown et al. (1998). Central Basin and Range- Shadscale-Dominated Saline Basins Ecoregion, 13b (Woods et al., 2001).

Summary Note: Three distinct range plant communities were presented below. Based on published designations and descriptions of these (or very similar) natural plant communities the three kinds of range communities were interpreted as climax (potential natural) range vegetation. In these three kinds or types (subtypes, perhaps) of climax range vegetation the only vascular plant species that was a consistently present and usually as the dominant (at community wide scale) was Nevada Mormon tea, Nevada ephedra, or Nevada jointfir. Winterfat was the dominant shrub and Nevada ephedra the associate shrub on one of these rangeland cover types. The main two native herbaceous plant species that were consistently present as major--though not always as dominant-- species were the sod-forming grass, galleta, and the cespitose bunchgrass, Indian ricegrass. A grass common to and widespread on both Chihuhuan-Sonoran and Great Basin semidesert grasslands was the highly variable, perennial threeawn of the Aristida purpurea complex. Alkali sacaton was another grass that occurred (and inconsistently so) on semidesert grasslands in both of these diverse areas of the Basin and Range province. A major difference between these two regional semidesert grasslands was absence of a major gramagrass (Bouteloua sp.) on Great Basin types. Cheatgrass or downy brome, the ubiquitious naturalized Eurasian annual grass, was always "represented" on climax Great Basin grasslands, but it was far less common or abundant than any of the native perennial grass species. Cheatgrass was usually limited to extra-wet microhabitats such as deep cow tracks, entrances to rodent burrows, or, as shown below, at edges of harvester ant mounds.

An arborescent member of the Liliaceae that would be an approximate ecological equivalent of soaptree yucca was absent from the Great Basin semidesert grasslands. This was a conspicuous dissimilarity among the two general regional types.

The "everywhere" presence of galleta and, especially, Nevada jointfir in this Great Basin range vegetation corresponded to widespread dominance of tobosagrass on swales and omnipresence of longleaf jointfir or Mormon tea (E. trifurca) in climax vegetation of the Chihuhuan Region. The seemingly ecological equivalents (natural or climax dominant species over large expanses of natural range vegetation dominanted by grasses) of two species of Hilaria and two species of Ephedra constituted conclusive proof to this author of the close floristic relatedness of semidesert grasslands within these two vast parts of the Basin and Range physiographic province. It was emphasized previously that Dick-Peddie (1993, p. 116) interpreted longleaf jointfir as a diagnostic climax plant species of Chihuhuan semidesert grassland. Herein Rosiere extended the conclusion of Dick-Peddie (1993, p. 116) to Nevada jointfir on Great Basin range vegetation that was clearly dominated by grasses. Even though there were other climax shrub species in these kinds of natural herbaceous vegetation, Neveda Mormon tea was the only shrub that was present consistently (even if in small proportions) in these grass-dominated range plant communities.

Based on these diagnostic botanical characteristics Rosiere in this publication interpreted the Great Basin climax range vegetation presented below as semidesert grassland and not as shrub steppe. Logically some samples of these range plant communities could be seen and described as shrub savannahs (grassland with scattered shrubs), but with woody plant cover substantially less than that of such widely accepted shrub steppes as sagebrush-bunchgrass steppe. In eyes and mind of this author the physiogonomy and plant community structure were substantially different between, say, steppe co-dominated by bunchgrasses and sagebrush and the range vegetation shown below where stands of grass infrequently had an individual plant of a climax shrub species. General outward appearance, structure, and apparent species composition (relative amounts or proportions of cover or biomass) of herbaceous vegetation presented below and that of unquestioned semidesert grassland in southern parts of Basin and Range shown above undeniably portrayed the close similarity of these two regional grasslands.

Nonetheless, such conclusions unavoidably involved some value-judgments and therefore were arbitrary, at least to a point. Once more the individual reader can draw his own conclusions.

178. Bunchgrasses and sod-forming grasses in the semidesert- Mixed-grass steppe of galleta (Hilaria jamesii), alkali sacaton (Sporobolus airoides), various purple threeawns (Aristida purpurea complex), and Indian ricegrass developed across this far-flung basin with its large arroyos. This rangeland was on the upper border of and drained into the dry bed of Sevier Lake with the Beaver Mountains in the background providing a textbook example of Basin and Range topography. Range vegetation was a semidesert steppe consisting of both cespitose and sod-forming eragrostoide and festucoid grasses with widely scattered plants of Nevada Mormon tea, Nevada ephedra, or Nevada jointfir (Ephedra nevadensis).

Scarcity (almost absence) of cheatgrass (Bromus tectorum) and Eurasian crucifers (eg. Sisymbrium altissimum, Descurainia pinnata) "spoke volumes" as to climax or high seral status of this arid grassland range that was grazed by livestock as well as wildlife as part of a Federal allotment.

This semidesert grassland range was an example of "galleta-threeawn shrub steppe" described by West (in Barbour and Billings, 1988, ps.222-223, in West, 1983, ps. 413-421). The galleta-threeawn steppe range type covers larger areas east of this location such that this range was an "island example". Local dominance of alkali sacaton and presence of desert saltgrass (Distichlis stricta= D. spicata var. stricta) at lower elevation in background was consistent with a general description of Intermountain (Nevada) grassland by Tueller (1975, p. ). Presence (very sparse cover) of Nevada Mormon tea was discusssed in a Summary Note immediately above.

The combination of sod-forming clones of galleta and clumps of tillers of alkali sacaton, threeawn, and Indian ricegrass was obvious, especially in the first of these two photographs.

Bureau of Land Managaement, Fillmore, Field Office, Millard County, Utah. June, early estival aspect with phenological stages of grasses varying from dormance to "seed-ripe". FRES No. 40 (Desert Grasslands Grassland Ecosystem). K- 51 (Galleta-Threeawn Shrubsteppe). No SRM or, alternatively, Great Basin variant of SRM 712 (Galleta- Alkali Sacaton). No appropriate designation in Brown et al. (1998). Pleuraphis jamesii Herbaceous Vegetation (Nevada Natural Heritage Program, 26 September, 2003). Central Basin and Range- Shadscale-dominated Saline Basins Ecoregion, 13 b (Woods et al., 2001).

179. Mixed-grass semidesert grassland- Not exactly "a land flowing in milk and honey" but on this upland immediately above dry lakebed of Sevier Lake galleta, alkali sacaton, purple threeawn, Indian ricegrass, and Nevada jointfir formed a climax semidesert steppe. Physiogonomy and, to some extent, species composition of this range type was presented in this landscape perspective.

Desert pavement-like condition of land surface was shown in this photograph as well as the two preceding and three succeeding slides. In layman's terms this is a "hardland" or "tightland" habitat in contrast to sandy soils (soil texture classes with greater proportions of sand) of semidesert grassland range types shown below.

Millard County, Utah. Bureau of Land Management, Fillmore Field Office. June, early estival aspect with most grasses at "seed-ripe" stage and entering dormancy. FRES No 40 (Desert Grasslands Grassland Ecosystem). K-51 (Galleta-Threeawn Shrubsteppe). No SRM or, alternatively, Great Basin variant of SRM 712 (Galleta-Alkaki Sacaton). No appropriate designation in Brown et al. (1998). Pleuraphis jahesii Herbaceous Vegetation (Nevada Natural Heritage Program, 26 September, 2003). Central Basin and Range- Shadescale-dominated Saline Basins Ecoregion 13 b (Woods et al., 2001).

180. Stand of stand-alone threeawn- Individual plants (genetypes or genetically unique individuals) of purple threeawn formed a local stand of this prominently cespitose eragrostoid genus. Unlike the sod-forming dominant galleta, this and associated alkali sacaton and Indian ricegrass have asexual reproduction exclusively by tillers (vertical or intravaginated shoots).

Millard County, Utah. Bureau of Land Management, Fillmore Field Office. June, grain-ripe stage of phenology.

181. Purple threeawn- The Aristida purpurea complex in portions of the Great Basin includes threeawns that have at one time or another been interpreted as A. fendleriana, A. glauca, A. longiseta, and A. wrightii (Welch et al., 1993, p. 700). The same situation obtains for other range regions covered within the current publication as for example in the semidesert grasslands and deserts of the Chihuhuan and, to some degree, Sonoran Region. This was seen as some evidence of the affinity of semidesert grasslands in all of these regions, but it must also be remembered that the A. purpurea complex is well represented in range types of humid and subhumid climates such as tallgrass and mixed prairie grasslands.

Under more favorable environmental conditions A. purpurea is clearly a seral species (typically interpreted as an invader) whereas on semidesert grasslands of the Great Basin this taxonomic complex has been regarded as a defining dominant or associate member of the climax vegetation (eg. Kuchler [1964] map of potential natural vegetation). Even as a dominant of the climax range vegetation A. purpurea increases with heavier grazing (West in West, 1983, p.415) which is a response characteristic of an increaser or invader. Under almost all of these varied range environments A. purpurea is highly unpalatable to almost all kinds and classes of range animal. Hence, one descriptive common name is "no-eatum" (Welch et al., 1993, p. 790).

Millard County, Utah. Bureau of Land Management, Fillmore Field Offfice. June, hard-grain stage ("seed-ripe").

182. Bald in the middle- Like the narrow ring of turf around the slick dome of a bald-headed rangeman, alkali sacaton growing on semidesert grassland ranges in the Great Basin characteristically develops into large tufted plants that die out in the center (Welch et al., 1993, p. 872). Eventually the bare area of soil inside a large, ring-forming alkali sacaton plant may become a microsite or microhabitat more favorable for colonization by other plants. Thereupon, individuals of other species like galleta, Indian ricegrass, or cheatgrass invade and establish on the spot of land protected by the natural shelter of encircling sacaton tillers. The aging process of "going bald" was presented in the first photograph. Colonization by galleta and cheatgrass of the "bald knob" surrounded by sacton shoots was shown in the second photograph.

This development in the range plant community is an example of the facilitation process of plant succession (Connell and Slatyer, 1977) which, of course, is nought but an updated version (Barbour et al., 1999, p. 297) of the Clementsian model of ecesis and aggregation of invading plants due to improved habitat (growing conditions) following reaction brought about by plants previously occupying the sere (Weaver and Clements, 1938). This is an illustration of what Clements meant by "dynamic ecology".

Millard County, Utah. Bureau of Land Management, Fillmore Field Office. June, early estival aspect.

183. Bearing fruit under severe conditions- Panicle of alkali sacaton on an upland site overlooking the dry bed of Sevier Lake. Successful opportunist that it is, alkali sacaton was "hedging its bets". Rather than relying solely on asexual reproduction afforded by tillering this semidesert parent plant had also completed sexual reproduction by fruit production (which in Sporobolus species is an achene rather than a caryopsis).

Millard County, Utah. Bureau of Land Management, Fillmore Field Office. June, hard grain phenological stage.

184. Twists and turns of herbivory. Harvester ants facilitate; cheatgrass invades in response to reaction- A good headline can tell most of the story, and this incident is self-explanatory for rangemen who can "read sign". For green horns and tenderfeet (for whom much of this publication was written) a mound constructed by western harvester ants (Pogonomyrmex ) served as a "water-harvesting and collection system" with water that spilled off of the earthen cone and collected at its base serving as a favorable microenvironment for establishment and completion of the short life cycle of the invading Eurasian annual festucoid grass, cheatgrass or downy brome. This is the successional process of facilitation or reaction shown and described in the photographs and caption before last.

Millard County, Utah. Bureau of Land Management, Fillmore Field Office. June. Grain-ripe/grain-shatter (annual life cycle completed).

185. Semidesert (semi-?) grassland- An Indian ricegrass herbaceous consociation with shrub cover and/or density "enough to count". Presented here were "photo-plots" from two ranges having climax vegetation dominated by Indian ricegrass with galleta, alkali sacaton, and purple threeawn as minor grasses (present at small or even trace quantities) and having winterfat, big sagebrush, rubber rabbitbrush, and Douglas or viscid rabbitbrush as local woody associate species. Nevada jointfir or Nevada Mormon tea was always present overall, as a community associate and, locally, as a co-dominant with Indian ricegrass. The second-most widespread shrub on these two example ranges was winterfat, which was the major shrub on the next cover type of Great Basin semidesert grassland presented (shown below).

It was explained in the Summary Note above that with the species composition and structure of this climax vegetation the range plant community could be viewed alternatively (and arbitrarily) as either grassland or grass-shrub savanna. It was also explained, however, why this range dominance type was described herein as semidesert grassland and not shrub-steppe.

The Indian ricegrass-Nevada jointfir range vegetation shown here was classified as an association by the National Vegetation Classification System for Nevada (in close proximity to location of these examples) as was shown shortly. Physiogonomy and structure of this range community was strikingly similar to the black grama-Torrey jointfir semidesert grassland found in Trans Pecos and Rio Grande portions of the Chihuhuan Region, but a liliaceous shrub was lacking from this and all other observed types of Great Basin semidesert grassland.

Millard County, Utah. Bureau of Land Management, Fillmore Field Field Office. June, early estival aspect. FRES No. 40 (Desert Grassland Grassland ecosystem). No Kuchler designation. No SRM cover type. The Ricegrass Series (142.23) of Great Basin Shrub-Grassland (142.2), Cold Temperate Grassland (142.) in Brown et al (1998, p. 40).Ephedra nevadensis/ Oryzopsis hymenoides plant association (Bourgeron et al., 29 August, 1994); Ephedra nevadensis / Achnatherum hymenoides Shrubland (plant association) (Nevada Natural Heritage Program, 26 September, 2003). Central Basin and Range- Shadscale-dominated Saline Basins Ecoregion, 13b (Woods et al., 2001).

186. Nevada Mormon tea, Nevada jointfir, or Nevada ephedra (Ephedra nevadensis)- An individual plant of Nevada jointfir on each fo the two ranges shown in the two preceding slides.

Millard County, Utah. Bureau of Land Management, Fillmore Field Office. June, pre-bloom stage.

187. Limbs and branches- Branches and characteristic branching pattern of Nevada Mormon tea. On the range Nevada jointfir is distinguished from the very similar green jointfir (E. viridis) by the grayish-green color and widely spaced branches of the former. Both species are valuable browse for wildlife and, among kinds of livestock, especially sheep (Welsh et al., 1993, p. 30).

Millard County, Utah. Bureau of Land Management, Fillmore Field Office. June, pre-bloom stage.

188. Rough-lookin' but beautiful- Only the third full day of summer and this range already looked "burnt up", but only to the "newcomer". This climax Indian ricegrass-galleta-winterfat range was at peak standing crop (it had been lightly grazed) with winterfat at full-bloom. Nevada ephedra was present, but as the associate shrub. Galleta was present as the second most abundant grass while threeawn was nearly absent. Cheatgrass was present, but limited almost entirely to areas of disturbance like road ditches and berms and places of rodent and harvester ant activity. This range plant community represented the potential natural vegetation for this range site and constituted a rangeland cover type.

This range vegetation was interpreted by the author as semidesert grassland (or at least as a savanna of widely scattered shrubs) and, as such, was included in this chapter. The cespitose (tufted) habitat of Indian ricegrass (ie. a bunchgrass) combined with cover of shrublike winterfat could logically lead to an interpretation of this climax range vegetation as a bunchgrass shrub steppe. This author however felt that cover of woody and/or semi-woody plants was conspicuously less than accepted standards of a shrub steppe as, for example, in case of sagebrush-bunchgrass shrub steppe. Furthermore and, as explained below, cover and biomass of winterfat is strictly speaking as much (probably more) herbaceous than woody. Therefore, in total this climax vegetation fit a designation of grassland more than a "hybrid" of grassland and shrubland.

Indian ricegrass has a rather unique set of morphological and genetic features and, consequently, an interesting history of taxonomic treatment. Welsh et al. (1993, p. 877) presented a thorough yet succinct summary of the situation. Iinterested students were encouraged to read their explanation (it is much more objective than radical treatments by cladistically oriented taxonomists). Indian ricegrass has morphological features in common with the needlegrasses (Stipa species in traditional American nomenclature) including a sharp callus on the caryopsis and large awn on the lemma. Thus at one point in taxonomic time Indian ricegrass was included in Stipa (S. hymenoides). Later, the deciduous awn (versus permanent awn in other Stipa species and ovoid-shaped grain led agrostologists to place this species in Oryzopsis (= O. hymenoides). Subsequently Indian ricegrass was "reinstated" as S. hymenoides. This revision was soon revised so that by the chaotic and, in this rangeman's mind, radical treatment of the "new agrostology" this remarkable range grass was designated Achnatherum hymenoides. It is doubtful if this is the last name given the "puplish-or-perish" hysteria of "run-it-like-a-business" modern universities combined with the relative ease (compared to actual experiments with live plants and animals) with which plant taxonomists can get a peer-reviewed paper out of a re-interpretation of a taxon.

Unfortunately, the Society for Range Management (Shiflet, 1994) did not recognize any Indian ricegrass rangeland cover type. It was remarked periodically in this publication that recognition of range cover types by the SRM is like recognition of human award recipients: someone has to nominate and write them up. That Indian ricegrass was minus such an advocate is not evidence that there is not an Indian ricegrass dominance type. There is. Readers of this work have seen three such range cover types in this chapter.

This Indian ricegrass-winterfat range represents some of the best of winter range. In much of this region surface water is lacking and water wells are so limited that livestock grazing requires water hauling for spring or summer use or, alternatively, has to be limited to winter sheep grazing. (If sheep are supposedly so stupid why do they know to eat snow and cattle do not?). Winterfat and Indian ricegrass "cure well" (ie. retain a high proportion of nutrients during winter and other periods of dormancy). Such ranges, as well as those that are composed almost strictly of winterfat (a consociation), are also ideal for pronghorn (Antilocarpa americana). One commonly sees--usually at considerable distance-- nice herds of pronghorn feeding on such semidesert grassland ranges.

Much of the brown herbage (which seemed to "overpower" green, growing plant material) was residue from the previous growing season. Due to the "curing on the vine" feature of herbaceous material, including that of winterfat which is described as suffruticose (becoming woody or somewhat of a shrub; basal parts of the plant are woody while upper portions are largely herbaceous), even "last year's stuff" is valuable feed. To the desert-wise rangeman this is indeed beautiful range.

Millard County, Utah. Bureau of Land Managaement, Fillmore Field Office. June, early estival aspect (anthesis in winterfat, "seed-ripe" in galleta, pre-bloom in Indian ricegrass). FRES No. 40 (Desert Grassland Ecosystem). No Kuchler unit. No SRM. Ricegrass Series (142.23) of Great Basin Shrub-Grassland (142.2) of Brown et al. (1998, p. 40). Ceratoides lanata / Oryzopsis hymenoides (Bourgeron et al., 29 August, 1994); Krascheninnikovia lanata / Achnatherum hymenoides Dwarf-shrubland (plant association) (Nevada Natural Heritage Program, 26 September, 2003). ACentral Basin and Range- Shadscale-dominated Saline Basins Ecoregion, 13b (Woods et al., 2001).

189. Makes 'em "fat and sassy"- Detail of the Indian ricegrass-winterfat vegetation from the range shown in the two preceding slides. Three plants of both of these range species were clearly visible in this photograph.

Millard County, Utah. Bureau of Land Managaement, Fillmore Field Office. June: winterfat at full-bloom and Indian ricegrass at pre-bloom phenological stages.

190. Queen subshrub and rest of the royal family- Typical specimens of winterfat (in full-bloom) surrounded by shoots of Indiant ricegrass, galleta, and cheatgrass. Cheatgrass, too? Yes, of course. Royal families were infamous for their bastards and other remittance men. Present were both current and previous growing season's biomass, woody and herbaceous plants, annuals and perennials, native and exotic (but naturalized) species. Considerable biological diversity on an otherwise "dull" or "boring" range.

Winterfat is regarded as a subshrub or undershrub, a suffruticose species characterized by having a woody or semi-woody basal stem and producing new main limbs or branches during each growing season so as to appear to at least partially "die back" to or near the ground or land surface. Many more photographs, including flowering shoots, of winterfat were shown in the chapter, Great Basin Desert (winterfat cover type).

Millard County, Utah. Bureau of Land Management, Fillmolre Field Office. June.

191. Bunchgrass semidesert grassland- Example of needle-and-thread-Nevada jointfir semidesert grassland on a slope of deep sand. Other grassses present in very small proportions were galleta, Indian ricegrass, and, at even less cover, cheatgrass or downy brome. The only forb of consequence was pale evening primrose (Oenothera pallida) and it was limited to small areas of sand blowout.

Almost exclusive coverage of the herbaceous layer by the cespitose needle-and-thread resulted in a much more tufted appearance than was the case with semidesert grasslands dominated less exclusively by the cespitose Indian ricegrass. Galleta was far less common on this type than on any other kind of Great Basin grassland encountered. Cheatgrass was almost nonexistant when ompared to typical variations in cover and density of other Great Basin semidesert grasslands. Diagnostic presence of Nevada jointfir was a common feature of all types of semidesert grasslands observed in these parts of the Intermountain Region.

This obvioulsy climax range vegetation was not described in the standard works on Great Basin vegetation. The striking photogenic features of this range plant community (along with sharp callus on the Stipa caryopsis and pointed tips of jointfir branches) should have made this an obvious range cover type or subtype (ie. needle-and-thread semidesert grassland or perhaps Nevada ephedra-needle-and-thread steppe). Vegetation classification remains an unfinished task.

This semidesert grassland (or shrub steppe) range type is outstanding habitat for pronghorn a large herd of which vaminosed just as this vegetation-focused photographer stomped in on the otherwise tranquil range ecosystem.

Millard County, Utah. Bureau of Land Management, Fillmore Field Office. June, estival aspect (grain-shatter stage in needle-and-thread). No Needlegrass Series (and there should be) under Great Basin Shrub-Grassland (142.2) in Brown et al. (1998, p. 40). Closest designation in the National Vegetation Classification System would be Stipa comata Alliance (Bourgeron et al., 29 August, 1994). There should be a Heterostipa comata / Ephedra nevadaensis Shrubland (association-level natural plant community) if and when there is a published National Vegetation Classification for Utah.

192. Sticky characters- The team of needle-and thread and Nevada jointfir showed up for a range "photo-op". These two main (monopolizing is more apt) range plants of this semidesert grassland were presented as a "curtain call" of this small cast of characters. Plant species in the Great Basin are considerably less "armed" than those of other range types whose leading actors include cactus, woody legumes, and dagger-leaved yuccas. Nonetheless sharp, penetrating calluses of needle-and-thread and pointed tips of jointfir justify the high-topped boots and chinks of buckeroos fortunate enough to ride such outstanding range.

Species composition of needle-and-thread-Nevada Mormon tea Great Basin semidesert grassland.This range type was not reognized in any of the standard works on Great Basin vegetation.

MIllard County, Utah. Bureau of Land Management, Fillmore Field Office. June (post "seed shatter", pre-dormancy in needle-and-thread).

193. Not exactly an oasis, but a grassland in the desert- A desert saltgrass (Distichlis spicata= D. spicata var. stricta= D. stricta)-semidesert grassland had developed on this small basin where surface runoff water (both snowmelt and rain) from the mountain sides and inflowing water from neighboring Great Salt Lake resulted in soil moisture conditions (Clements' chresard) that were more mesic than that of the adjacent and predominant black greasewood-dominated salt desert shrub.

The lighter green or grayish-green strip behind the zone of saltgrass was a Utah samphire (Salicornia utahensis)-saltgrass zone in which samphire was the prominent species and the obvious dominant. The zone of range vegetation immediately behind the samphire-saltgrass vegetation (at base or toeslope of mountain) was a greasewood-samphire-saltgrass shrubland. (This greasewood-salt desert shrubland and adjoining samphire-grass zonal range communities were covered in the chapter, Great Basin Desert, Great Basin Greasewood.) This semidesert grassland and adjoining samphire- and greasewood-dominated range types constituted a halosere. The halosere made up of this saltgrass grassland and the other range cover types displayed here where was also described under Great Basin Desert (the section on Great Basin Greasewood). This land was traditionally refered to as an alkali flat.

All of these halophytic (adjective referring to "salt-loving" plants) plant communities were seen as climax vegetation. Shantz (in Tidestrom, 1925, ps. 19-21) used the original monoclimax model of Frederick E. Clements to describe the Salt Desert Shrub (perhaps the first usage and original literature source of this designation). Shantz interpreted the greasewood- and samphire-dominated range communities as Clementsian associations (ie. greasewood association, samphire association) while he regarded saltgrass grassland as the seral unit of associes (ie. saltgrass associes). In the original Clementsian model of plant succession any vegetation that was not determined primarily or ultimately by climate was seral. In the monoclimax model any plant communities that developed on land receiving more water than provided directly by precipitation (eg. most wetlands like marshes and riparian, floodplain, or other overflow water-derived vegetation) would be seral and regarded as a Clementsian associes. Thus designation of saltgrass associes by Shantz (in Tidestrom, 1925, ps. 19-21). Under polyclimax theory saltgrass semidesert grassland is climax range vegetation.

Range vegetation on the predominant north-slope of mountain sides was bluebunch wheatgrass-dominated bunchgrass steppe. This steppe-form of grassland has not been regarded as semidesert grassland by serious students of native vegetation. Such was also the situation here where bunchgrass range had a generally more moderate habitat (cooler temperatures, non-saline or -brackish water, non-alkali soils).

Desert saltgrass apparently was of too small a spatial scale to have a Kuchler "vegetation type" unit. Likewise the Society for Range Management (Shiflet, 1994) did include a Saltgrass rangeland cover type (probably could not find anyone to write it up). Neither was there a saltgrass biotic community in Brown et al. (1998). Apparently the saltgrass rangeland cover type (there is one--as clearly shown here and by the cited work of H.L. Shantz--even if it was not published) is a "Nobody love me" or Rodney Dangerfield "I don't git no respect" grassland. Saltgrass semidesert grassland would be a unit under FRES No. 40 (Desert Grasslands Ecosystem). Generally, Central Basin and Range- Shadscale-dominated Saline Basins Ecoregion, 13b (Woods et al., 2001).

Tooele County, Utah. June.

194. Forage and alkali- This cattle range of saltgrass-Utah samphire grassland on an alkali flat had been heavily grazed (proper use or overuse?) less than two months before this photograph was taken. Most (in some spots, almost all) saltgrass herbage had been removed by grazing thereby leaving a disproportionate cover of samphire (selective grazing).

It must be borne in mind that Utah samphire is a climax range plant. Shantz (in Tidestrom, 1925, ps. 19-21) recognized the samphire association that was made up of this perennial species and the annual western samphire (Salicornia rubra). The range considered here was a "combination" of samphire and saltgrass. However, as was shown in photographs that follow, natural vegetation that had been excluded from cattle grazing was primarily saltgrass.

Designations of this range vegetation was presented above. It is a Saltgrass rangeland cover type, but this was not recognized (or it was overlooked) by the Society for Range Mangement (Shiflet, 1994). Tooele County, Utah. June.

195."Do you always do this or was this the first time?"- Heavy degree of use on desert saltgrass occurred on a saltgrass-Utah samphire semidesert grassland range. Cattle had been taken off this range less than two months before this photograph was taken. The ungrazed (at least hardly touched) range plants were Utah samphire. The small tufts of herbage were clonal units of desert saltgrass on stolons that remained following cattle grazing. Degree of use can be guaged by comparison with ungrazed saltgrass in the next two photographs below. It was obvious that utilization had been heavy, but whether this was overuse or proper use on this range was not determined. Precipitation amounts and frequency during preceding winter and current spring were average or slightly above. If this heavy or high degree of use is proper (as evidenced by persistence of saltgrass under this extent of utilization in most years), this grass species--at least on this range site--is remarkable for grazing tolerance. If this high defoliation (heavy use) was more intense than typical, the question is raised if this will remain a saltgrass range or if it will degrade into a samphire stand (ie. a grazing disclimax). Altenatively, current grazing management might be part of a larger grazing program in which this range will be ungrazed in subsequent growing season(s). The range examiner must always regard grazing practices and outcomes in this light. Things on the range must be taken in context of the specific range (based on range sites) and its management and management objectives.

Tooele County, Utah. June, hard-dough grain stage in saltgrass. Desert saltgrass-Utah samphire semidesert grassland. Saltgrass rangeland cover type (unpublished).

Now to the exclosure.

196. Ungrazed desert saltgrass- Sward of ungrazed saltgrass immediately adjacent to but across a five-wire fence from the range that had been heavily grazed (high degree of utilization) as shown in the preceding slide. Adjacent location ruled out differences due to soil moisture, salt, and other nongrazing variables. Mere visual comparison of this range herbage gave a rough estimate of degree of use that had to be described as heavy. Whether this was proper or imporper degree of use (hence, grazing management) was not known. Only experience and/or experimentation over a sufficient period of time can provide the answer.

There was conspicuously less cover and density of Utah samphire in range vegetation that not been grazed by cattle. It was not known how many years (grazing seasons) cattle had grazed the range shown above or had been excluded from the ungrazed part. Therefore it could not be determined if the greater proportion of samphire on grazed rangeland was due to grazing or some other factor. Clearly there was a difference, quite a difference, in species composition.

Tooele County, Utah. June, hard-dough stage in saltgrass. FRES No. 40 (Desert Grasslands Ecosystem). No Kuchler unit ("vegetation type") at this spatial scale. Saltgrass rangeland cover type, but this was not published by the Society for Range Management (Shiflet, 1994).

197. What a difference water makes in the desert- Drainage of water from both inflow of salt water out of Great Salt Lake and overland flow of fresh water from a hillside produced this pronounced zonation of range vegetation at small-scale and discrete pattern. Foreground vegetation was part of the stand of desert saltgrass (with some Utah samphire) that was shown in the immediately preceding photograph. Midground vegetation (tall, green shoots) was a narrow strip of tule marsh made up of common three square, a bulrush, (Scirpus pungens) growing in and immediately surrounding standing water. Background vegetation (barely visible) was terminus of an alluvial fan populated by black greasewood and viscid rabbitbrush.

The tule marsh and adjoining wetland vegetation was covered in the chapter, Meadows (Flood Meadows).

198. Desert saltgrass (Distichlis stricta= D. spicata var. stricta= D. spicata)- Example of desert saltgrass growing in the saltgrass-Utah samphire semidesert grassland range featured above (obviously in the exclosure) This large clump of tillers was growing as a clonal unit from a rhizome of this colony forming eragrostoid grass. Saltgrass is frequently both rhizomatous and stoloniferous. This individual was in hard-dough grain stage of phenology.

Tooele County, Utah. June.

199. Utah samphire (Salicornia utahensis)- This perennial, succulent chenopod was a second menber of the desert saltgrass-Utah samphire semidesert grassland discussed above. This species varied from being co-dominant, dominant, or subordinate (associate) to desert saltgrass. Possible role of cattle grazing was considered in above discussions.

Tooele County, Utah. June.

The following two photographs were of range vegetation along a catena on a low hillside in the eastern Great Basin. Range plant communities developed on different range sites in a zonal pattern that reflected edaphic and topographic features of the land. Two of these distinctive zonal range communities had the physiogonomy, community structure, and species composition of grassland. These were not mountain, riparian, or wetland grasslands and, instead, possessed characteristics of Great Basin semidesert grasslands including some of the dominant grass species that defined semidesert cover types presented above. These grasslands also had features in common with Great Plains semiarid mixed prairie, especially in regards to dominant grass species.

Absence of Nevada jointfir and an ecological niche or role of western wheatgrass--as either a dominant or associate species-- distinguished the more xeric (and probably, to most viewers, more obvious) semidesert grasslands from the two immediately following Great Basin vegetation that seemed to more nearly fit designation of shrub steppe.

These two examples were included in both the Semiarid Grasslands and Shrub Steppe chapters. This reflected the arbitrariness which cannot be avoided when typing some range plant communities. Also, this reflected the frequent continuum existing in natural vegetation. Inclusion of these examples of Great Basin herbaceous and/or herbaceous-woody vegetation at this point was intended to avoid confusion and to allow readers to navigate from one category of range cover types to the next.

200. When range vegetation plays by the rules- Textbook example of sagebrush shrub steppe: Indian ricegrass-mountain big sagebrush dominated rangeland with major associated grasses being needle-and-thread, western wheatgrass, galleta, and with cheatgrass a minor component species except where locally dominant on disturbed patches. Associated but widely scattered shrubs included rubber and Douglas or viscid rabitbrush and antelop bitterbrush.

Lower down on the sideslope, which and developed and functioned as a catena, western wheatgrass had displaced needle-and-thread as the main associate to Indian ricegrass and big sagebrush had replaced rabbitbrush as the dominant shrub.

All in one's perspective: this climax vegetation fits "perfectly" (at least "closely") with the ideal example of sagebrush shrub steppe. Conversely, this range plant community could be interpreted as semidesert grassland from perspectives of physiogonomy, obvious dominance by grass (cover and density), prevalence of herbaceous layers over woody plant cover, and greater biomass from grasses than shrubs. One potential basis for distinction between shrub steppe (a savanna by definition) and semidesert grassland is that of greater aridity or xericity of habitat with the latter being the driest of all major North American grasslands.

Absence of an Ephedra species from the grass-dominated Great Basin vegetation presented here in contrast to widespread occurrence of and, typically, dominance by E. nevadaensis on what are obviously semidesert grasslands (or closer thereabouts) elsewhere in the Great Basin suggested that the climax plant community above was shrub steppe not semidesert grassland. In such matters the individual reader-viewer will decide.

Juab County, Utah. June, early estival aspcet but most grasses progressing rapidly toward completion oa annual growth and dormancy. Most logical interpretation of this range vegetation in author's view was FRES No. 29 (Sagebrush Shrubland Ecosystem). K-49 (Sagebrush Steppe). SRM 402 (Mountain Big Sagebrush). Great Basin Shrub-Grassland 142.2- Ricegrass Series 142.23 (Brown et al., 1998, p. 40). Artemisia tridentata / Achnatherum hymenoides Shrubland (a plant association) (Nevada Natural Heritage Program, 26 September, 2003; there being no such classification for neighboring Utah). Central Basin and Range- Sagebrush Basins and Slopes Ecoregion 13c (Woods et al., 2001).

201. Sagebrush shrub steppe or semidesert grassland? (Or your guess as good as the next rangeman's.)- The lowestmost range plant community on the catena featured here was--depending on one's perspective and other biases--either a western wheatgrass-mountain big sagebrush steppe or a consociation of western wheatgrass having such a paucity of big sagebrush as to be a grassland. Indian ricegrass, needle-and-thread, and galleta were the other major (though only associate) grass species. Cheatgrass was "few and far between". Rabbitbrush species hardly qualified as associates to mountain big sagebrush.

On this catena-arrayed series of climax range communities western wheatgrass increased consistently until at lowest elevational zone western wheatgrass displaced Indian ricegrass as the dominant range plant. On the deeper, more mesic (or less xeric) edaphic environment the rhizomatous, colony forming habit of western wheatgrass had a decided competitive advantage over the strictly cespitose Indian ricegrass. With less bare soil available the prolific grain yields of Indian ricegrass was not the superior adaptation it is on more xeric habitats.

Juab County, Utah. June, early estival aspect but all grasses were speeding toward dormancy. The most rational perspective on this range vegetation in the author's judgment was FRES No. 29 (Sagebrush Shrubland Ecosystem). K-50 (Wheatgrass-Needlegrass Shrubsteppe). Not a close fitting rangeland cover type (Shiflet, 1994); Western Wheatgrass variant of SRM 402 (Mountain Big Sagebrush) or, descriptively but outside the Great Basin, Great Basin variant of SRM 607 (Wheatgrass-Needlegrass). Great BasinShrub-Grassland 142.2- Wheatgrass Series 142.21. Central Basin and Range- Sagebrush Basins and Slopes Ecoregion, 13c (Woods et al., 2001).

The San Luis Valley in southcentral Colorado is regarded as one of four Intermountain Parks within the Southern Rocky Mountains. Fenneman (1931, ps. 130-132) described the San Luis Valley as a structural basin situated between the Sangre de Cristo Range to the east and the San Juan Range to the west. San Luis Valley has been interpreted as part of the general Rio Grande Rift System as upper reaches of the Rio Grande flow through this basin with streams that flow into the river forming alluvial fans (Fenneman, 1931, p. 130). The surrounding mountain ranges function as barriers to precipitation and the general land form resembles that of the Basin and Range province. Aridity is the local climatic result of this land form (ie. barrier and basin) with annual precipitation ranging from approximately seven to ten inches and averaging less than eight inches. Therefore the San Luis Valley is, strictly speaking, a climatic desert within the Southern rocky Mountains (James, 1971). Trimble (2001) described the San Luis Valley as the largest, highest mountain desert in North America.

Within this mountain desert there are three major and general (large spatial-scale) range types: desert scrub dominated by black greasewood (Sarcobatus vermiculatus) and with rabbitbrush (Chrysothamnus spp) as associate shurbs; 2) desert (technically, semidesert) grassland of Indian ricegrass (usually the dominant), various muhleys (Muhlenbergia spp.), and blue grama; and 3) a savanna of black greasewood-Indian ricegrass-muhly. This savanna developed primarily on vegetated sand dunes whereas the semidesert grassland developed on non-dune land having somewhat less sandy soils and the greasewood scrub .

Location note: the greasewood scrub or greasewood-dominated desert was included in the shrubland chapter entitled Miscellaneous Scrub Types.

A beautiful grassland (or savanna in local sites) that was not given in the SRM rangeland cover types was an Indian ricegrass (Oryzopsis hymenoides)-dominated (the consistent dominant) range plant community with other major grasses being ring or blowout muhly (Muhlembergia torreyi), sandhill muhly (M. pungens), blue grama (Bouteloua gracilis), mat grama (B. simplex), and on deeper sands, needle-and-thread (Stipa comata) and with black greasewood (Sarcobatus vermiculatus) as the major woody species and plains pricklypear (Opuntia polyacantha var. rufspina) the other shrub, these two with the midgrasses sometimes forming a sparse savanna. There were occasional plants of bottlebrush squirreltail (Sitanion hystrix), but aside from species diversity this grass had little indicator value for this range type. In range plant communities where needle-and-thread was an associate to co-dominant (deeper dunes) there was very little blue grama. Forbs were scarce to non-existent.

In some areas there were fairly deep and pronounced sand dunes whereas in other areas the land surface was less hummocky, rolling , or choppy (less dune-like) and more flat in local microtopography. Needle-and-thread more-or-less replaced blue grama as an associate grass species on the deeper dunes.

This grassland and the greasewood-grass savanna were contiguous with greasewood-dominated scrubland that was the climax range vegetation on alkaline flats (alkali basins). or eru

202. General sand dune type of mixed species semidesert grassland- A semidesert grassland dominated by Indian ricegrass and with sandhill muhly (M. pungens), ring or blowout muhly (Muhlenbergia torreyi), needle-and-thread, blue grama, and mat grama as associates (varying with local microsites) that developed on sand dunes in the San Luis Valley. Black greasewood was the major woody species which ranged from absence through associate to co-dominance with Indian ricegrass. Plains pricklypear was also preent and locally common. This range vegetation varied from grassland to greasewood-grass savannah at local scale.

These two photographs presented this climax range plant community at greater spatial scale so as to show physiogonomy and the considerable variation in structure and species composition. The first photograph including a local stand of blue grama with some mat grama (foreground) surrounded by numerous plants of black greasewood and Indian ricegrass as co-dominants. This variant of the sand dune semidesert grassland prevailed on land with lower dunes and shallower soil. the The second photograph displayed the Indian ricegrass-black greasewood savana form in which needle-and-thread was the major associate species. this vegetational variant predominated on deeper sands (higher dunes).

Great Sand Dunes National Park, Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No Kuchler unit because he mapped it as K-34 (Saltbush-Greasewood) when this is semidesert grassland within K-34. No SRM unit. Closest thing in Brown et al. (1998, p. 40) was Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series, 142.22 and that ain't it. Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

203. Indian ricegrass-black greasewood savanna- A savanna of these two co-dominants with needle-and-thread as the associate species which was the range plant community most widespread on the higher dune (deeper sand) portion or form of this overall semidesert grassland vegetation that developed in the San Luis Valley. There were isolated plants of blue grama, mat grama, sandhills muhly, and ring muhly, but these were not major species (based on cover, density, general abundance) in contrast to low dune areas where black greasewood and needle-and-thread were less common.

These two photographs showed the range plant community at a smaller spatial-scale than that of the two preceding slides in order to show the interior structure of this vegetation as well as growth form and habit of Inidan ricegrass and black greasewood, co-dominants of major portions of this savanna. The next slide featured habit along with relative cover and spatial relations between the two co-dominants.

Great Sand Dunes National Park, Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No Kuchler unit because he mapped it as K-34 (Saltbush-Greasewood) when this is semidesert grassland within K-34. No SRM unit. Closest thing in Brown et al. (1998, p. 40) was Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series, 142.22 and that ain't it. Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

204. Sharing the dunes- Indian ricegrass and black greasewood were frequently co-dominants as a savanna on major portions of a general semidesert grassland type dominated overall by Inidan ricegrass with varying proportions (based on relative cover) of blue grama, needle-and-thread, sandhill muhly, ring muhly, and mat grama as associate grasses. Plains pricklypear was the second important woody species.

The cespitose (tufted or clumped) habit of Indian ricegrass, a bunchgrass, and the size and shape of black greasewood on deeper and vegetated sand dune was featured in this photograph. On adjoining alkali sinks and flats the dominant black greasewood (with minor portions of Chrysothamnus species) and an erratic herbaceous cover of galleta (Hilaria jamesii) formed local cold desert or scrubland in the San Luis Valley where this set of photographs was taken. On greasewood desert scrub individual, adult plants of black greasewood were substantially larger than on duneland savanna. Squirreltail bottlebrush, a grass of the barley or wheat tribe, joined Indian ricegrass as the other locally important grass. Although of little value as an indicator species in this range vegetation, presence of the uncommon squirreltail bottlebrush demonstrated the species diversity--especially at local scale--of sand dune semidesert grassland and savanna.

More species diversity was reviewed in the two immediately following slides.

Great Sand Dunes National Park, Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No Kuchler unit because he mapped it as K-34 (Saltbush-Greasewood) when this is semidesert grassland within K-34. No SRM unit. Closest thing in Brown et al. (1998, p. 40) was Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series, 142.22 and that ain't it. Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

205. Cast of major players on sand dune semidesert grassland and savanna- "Lineup" of botanical actors on climax vegetation of arid rangeland that developed on sand dunes in the San Luis Valley, a mountain high desert. Different local to area combinations of various cespitose grass species and two or three shrubs produced range plant communities ranging from bunchgrass prairie to a shrub savanna. The major plant species--the overall dominant--of dune vegetation was Indian ricegrass. This member of the Stipeae tribe formed extensive consociation of semidesert grassland in non-dune rangeland. The major shrub was black greasewood which was frequently co-dominant with Indian ricegrass (the most abundant, and climax, grass overall). Greasewood scrub--an area-wide, alkaline desert--was an adjoining range cover type so there were local transition zones (small ecotones) between the greasewood-dominated desert and semidesert grassland.

The "botanical actors" on this arid stage included Indian ricegrass (the most abundant, tallest, largest clumps of light green color in right foreground and left background of first slide), sandhillls muhly (most prominent as the conspicuous hemispherical-shaped groups of clumps with bent dead stalks along with darker green leaves in right foreground of second slide), ring muhly (large circular clump with sparse center in left foreground of second slide), blue grama (most covr in left fore- and midground of first slide), mat grama (not present as visible), plains pricklypear cactus (left midground of first slide; left-center midground of second slide), and black greasewood (larger shrub with dying portions in right mid- to background and small, bright-green shrub to right of pricklypear in second slide).

Great Sand Dunes National Park, Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No Kuchler unit because he mapped it as K-34 (Saltbush-Greasewood) when this is semidesert grassland within K-34. No SRM unit. Closest thing in Brown et al. (1998, p. 40) was Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series, 142.22 and that ain't it. Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

206. Two bunchgrass dominants on a semidesert grassland/savanna- Indian ricegrass (seven plants foremost in first slide, five plants at rear of second slide) and sandhills muhly (seven or eight plants in front of Indian ricegrass in second slide) on sand dune range vegetation in the San Luis valley. Indian ricegrass was the overall dominant herbaceous species (often co-dominat with black greasewood on savanna) while sandhill muhly was locally dominant to co-dominant of microsites with deeper sand. Both of these grasses have a tufted or clumped growth habit so as to have the cespitose (bunchgrass) form. Indian ricegrass is strictly cespitose having only tillers (vertical shoots) whereas sandhills muhly is semi-cespitose possessing large, coarse rhizomes from which it produces new modular units (= clones or "daughter plants"). These ramets or "sister plants" tend to grow in a circular pattern, a circumspatial arrangement of dispersion so to speak. (Ring muhly is also strictly cespitose and lacks horizontal shoots.)

It was shown in the immediately preceding two photographs and in photographs below that sandhill and ring muhlies tend to grow in a "ring" pattern. This phenomenon was explained in greater detail below. These photographs and captions remarked that in this dune vegetation grasses have the predominant bunchgrass (tufted) form due to predominance of asexual reproduction/growth via tillers rather than rhizomes or stolons which result in more of the sod-forming habit. Silveus (1933, p. 238) described both of these Muhlenbergia species as "dnesely tufted". Sandhills muhly produces new tufts as clones off of rhizomes with the whole or overall pattern being one of a rough "circle". The "ring" of ring muhly results from senescence and death of older (more interior) parts of the root crown. As the center dies out and youner tillers around the perimeter of the bunchgrass remain alive a "fairy ring" (Gould, 1975, 254; Shaw, 2008, 171). That die-off sequence explains some of the "ring" growth form of sandhills muhly, but not all of it. The tufts of tillers (ramets or clones) that arise from rhizomes of sandhill muhly eventually "close in the gaps" between themselves thereby creating a "fairy ring" even without a center die out phenomenon. Standard agrostological treatments of M. pungens (Barkworth et al., 2003, ps. 174-175; Shaw, 2008. p. 162) have overlooked or were unaware of this arrangement of vegetative growth.

Another probable factor in this circular pattern of shoot dispersion is production of new plants (new genotypes) sexually, from caryopses. An observation made on the range by this photographer was that even Indian ricegrass tends to have a circular pattern of dispersion with smaller (presumedly younger) plants around a larger (older) plant which was likely the parent of the smaller plants. This was shown in these photographs, especially the first one. Another interesting (and perhaps revealing or indicative) thing in these slides was the circular imprints in the soil surface left by windblown grass leaves. Wind "behavior" in/on duned land is a complex phenomenon resulting in, among other things, different kinds of dunes being formed. Surface wind patterns at microscale, such as on the windward or lee side or height up on a dune, could go a long way in explaining dispersal of grass grains and, thus, dispersion patterns of plants. Fruits--other than extremely light, parachute-equipped ones--tend to be dispersed in concentric zones around parent plants. Progeny plants tend to be dispropotionately concentrated around their parents greater due to this pattern of propagule dispersal (unless parent plants repel their progeny via competition or allelopathy).

There would be a tendency for many plant species to produce a "fairy ring"-like distribution of plants much like those of mushrooms or, in this case, grasses (even without die-out at the center of a tufted plant). Tolstead (1941) reported that sandhill muhly, needle-and-thread, and blue grama (among several others) produced viable seed that germinated even without influence of low-temperatue. Even if low temperatures enhanced germination, cold temperatures would not be a limiting factor as it gets "plenty cold" in the San Luis Valley which is a mountain basin desert in the Southern Rocky Mountains. Indian ricegrass produces some of the most abundant yields of grain (and of large grain size) of any North American native grass species-- as learned by the American Indians who harvested this grain and used it for a staple. Caryopses of Indian ricegrass also have limited germination due to seed dormancy, a survival characteristic that has received considerable study by range management specialists (Jones, 1990; Jones and Nielson, 1992; Jones, 2009). Various slides included in this section showed irrefutably that grains of Indian ricegrass do germinate and emerge adequately to maintain dense and, sometimes, exclusive populations of this species, including consociations-- single-species stands--over large areas of range (see below). Sexual reproduction is conspicous when there are high numbers of obviously individual plants (unique genotypes) of cespitose species.

In essence, some of the tufted plants of sandhills muhly were likely sexually produced genotypes as well as the more obvious clonal tufts arising from rhizomes. This was even more so for strictly cespitose species like Indian ricegrass, needle-and-thread, and, of course, the annual mat grama. A logical question that would make this point could be, How many of the seven or eight clumps of sandhills muhly in the forefront of the second slide are clonal or, same thing, how many are different genotypes? Contrary to what seemed the obvious, not all of clumps of Indian ricegrass are plants of a single unique genotypes. Investigations by McAdoo et al. (1983) revealed that some clumps of Indian ricegrass consisted of several genetically unique plants (ie. different genotypes) that sprouted from grain caches made by rodents. While all these plants began life as seedlings some tufts were composed of several genetic individual plants (in contrast to clumps of sandhill muhly many of which are modules or "sister plants" of the original seedling).

Great Sand Dunes National Park, Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No Kuchler unit because he mapped it as K-34 (Saltbush-Greasewood) when this is semidesert grassland within K-34. No SRM unit. Closest thing in Brown et al. (1998, p. 40) was Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series, 142.22 and that ain't it. Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

207. Reinvasion on "new land"- To an ecologist the designations of "new land" or "new ground" refers to disturbed land (often partially to largely denuded or devegetated). Disturbances vary from natural to man-made (admitting, of course, that man is part of Nature) with some of the latter including plowing, overgrazing, improper burning (or, more commonly, lack of burning), road construction, military maneuvers, recreational vehicle damage, etc. Abandonment of cropland (farm ground) results in "new land" known as "old fields" or "go-back land". Revegetation or recovery of vegetation through natural processes constitutes secondary plant succession. Denudation resulting from road-building activity frequently leaves road cuts with so little soil remaining that natural restoration has to start from the stage of parent material in which case the series of re-development of vegetation is primary plant succession.

The local denuded area shown here (and in the immediately following two photographs) was a road cut in sand dune semidesert grassland/savanna in the San Luis valley, a high desert in a mountain basin in the Southern Rocky Mountains. The bladed, devegetated area was a narrow strip of land between virgin vegetation. This arrangement or pattern in land space was shown in this photograph.

Age of this local disturbance was not known. This "scar (or wound) on the land" was relatively old. It was undoubtedly several years old. Obviously, it was being invaded by range plants most of which were sandhill muhly, ring muhly, and black greasewood with lesser cover of mat grama. Plants of the overall dominant species, Indian ricegrass, and associates needle-and-thread or, depending on local haibitat, blue grama hd not yet colonized the denuded strip of land. Invasion was the term given the Range Management profession by Frederic Edwards Clements which means the cumination, the endpoint, of successional processes (migration, ecesis, aggregation, competition, stability, etc.) resulting in movement of plants from one piece of land to another and establishment of new plants in the latter (Weaver and Clements, 1938, ps. 148, 166). Theoretically, there is no invasion in climax vegetation, only renewal or replacement of existing species (often by clonal or asexual reproduction). When land has been denuded through disturbance it becomes a "new" environment for migration of plant propagules (disseminules like fruit, seed, shoots) and their ultimate establishment (= invasion). Typically plant species that first reinvade (= pioneer or colonize) "new ground" like old fields and/or that increase under disturbances are designated invaders. With on-going development of vegetation through various plant communities over time on the sere, the piece of land on which plant succession progresses, of a given range or forest site eventually a final plant community becomes established as the climax vegetation. The climax remains relatively stability though this stability is more of a seesaw-like "dynamic equilibrium". Plant species that characteristically decline first under abnormal disturbance are given the designation of decreasers. An intermediate category of range plant species that initially increase under disturbance and then decline with continuing disturbance (and as invaders become established) are called increasers.

Invaders on severely disturbed areas like old fields are most commonly annuals surviving stressful periods as seeds or dried fruits (eg. grass caryopses) whereas decreasers are long-lived perennials with greater reliance on vegetative or clonal reproduction versus sexual reproduction (seeds, grains, spores). On the bladed road cut shown here there were very few plants of the annual and native mat grama or annual invaders like cheatgrass. Instead, the occupants were old plants of sandhill and ring muhly. Adjacent undisturbed vegetation was dominated by the climax dominants, Indian ricegrass and black greasewood along with blue grama and needle-and-thread and lesser cover of the Muhlenbergia species. This suggested that range vegetation currently occupying the road-cut disturbance was roughly mid-sere and, by extension, that perhaps the Muhlembergia species were increasers. Vallentine and Burzlaff (1964) classified sandhills muhly as an increaser and Indian ricegrass and needle-and-thread as decreasers or increasers depending on range site. Pound and Clements (1898) found that on fresh sand "blowouts" sandhills muhly came in with the second seral stage following colonization by blowout grass (Redfieldia flexuosa). Sandhills muhly persisted on blowouts where it sometimes comprised a faciation, the major subunit of a Clementsian association (Weaver and Clements, 1938, ps. 95-96). More on this in the next "installment": next slide, please.

Great Sand Dunes National Park, Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No Kuchler unit because he mapped it as K-34 (Saltbush-Greasewood) when this is semidesert grassland within K-34. No SRM unit. Closest thing in Brown et al. (1998, p. 40) was Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series, 142.22 and that ain't it. Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

208. Old rings on "new land"- Two "photoplots" provided closer-in views of sandhill and ring muhly (with a few plants of Indian ricegrass) populating an old road cut and "healing" this denudtion "wound on the range". The preceding photograph and caption provided a more distant and general view of this "site of disaster" that served as "new land" (an area of land available for revegetation). Also shown in that slide was adjoining undisturbed climax vegetation along with its caption that provided a summary of plant succession on the sere of this degraded range. That "installment lesson" ended noting that sandhill and ring muhlies as current occupants of this bladed area at mid-sere were perhaps increaser species and that plants of those two species were obviously rather old individuals.

The latter conclusion was based on knowledge of growth habit of Muhlembergia pungens and M. torreyii, sandhill and ring muhlies, respectively. Both of these perennial, eragrostoid grasses are cespitose (bunchgrass) species. Much of their growth/asexual reproduction is through addition of new tillers. An individual plant increases in basal area as new tillers are produced at the perimeter (around the outer edges) of the root crown so that older plants become larger (as measured at either basal or foliar cover). As individual plants of sandhill and ring muhly age and increase in diameter (grow wider across) through addition of peripheral tillers the older (the more interior) parts of these plants die so that eventually only a circular boundary of younger tillers remain. This growth pattern results in a uniuque and very characteristic "ring" of tillers. Hence, the common name, ring muhly, taken from the circular pattern or growth habit of clonal shoots. Some of these "rings" reach diameters of considerable size. The author stepped off some circular arrangements of muhly tillers shown in these photographs that reached from six to ten feet in diameter. Presumedly the larger plants (those with greater-diameter clonal "rings") growing at a given location are older than adjacent or closely neighboring plants of smaller size.

This circular pattern of tillers or growth habit in ring and sandhill muhly has been widely recognized and described by workers as, for example, Gould (1975, ps. 254, 255) and Shaw (2008, ps. 162, 171) This growth phenomenon has been commonly attributed to the incremental death of older more interior parts of plants (seemingly senescence of older portions of the root crown). Observations by this author found this explanation to be inadequate, at least in the instance of sandhill muhly. Although sandhill muhly is cespitose it also grows coarse, rank rhizomes (Gould, 1975, p. 254; Shaw, 2008, p. 171). The current author found many plants of sandhill muhly on the ranges presented here that had produced new clonal units (= ramets, offshoots, modules) off of their rhizomes. The rhizomatous "sister plants" or "daughter plants" had been produced in a circular arrangement so that they had grown into a "ring". This clonal "ring" was not due to senescence and death of the interior of a cespitose plant, but rather from an increase in numbers of daughter or sister offshoots which themselves grew in diameter through tiller proliferation and "when it came their turn" produced daughter modules themselves. In other words, the standard "died out in the middle" leaving a "fairy ring" description (Gould, 1975, ps. 254, 255) is an incomplete explanation for the "ring" growth habit. Again, this is the case at least for sandhill muhly. Incidentially, it appeared to this photographer that all of the extremely large rings of sandhill muhly (eg. those reaching six to eight feet across) were result of ramets growing in a circular arrangement and not due to death of interior tillers (older parts of the root crown). It seemed highly unlikely that a bunchgrass could grow to such dimensions in this high desert environment. Is was also possible that some of the clumps in the erratic " fairy circles" were other genotypes (different plants) that developed from fruits (achenes in Muhlembergia species) from sexual reproduction.

Viewers can see for themselves the individual "bunches" (ramets or "sister plants") in several of these rhizome-produced muhly "circles" or "rings" in both of these photographs, the second from the last photograph above, and in foreground of the immediately succeeding photograph.

Dominance of this bladed area (the upper slope of borrow ditch on a a road cut) by muhly species rather than Indian ricegrass, needle-and-thread, black greasewood, and (maybe) blue grama indicated that this Muhlenbergia-dominated plant community was a seral stage--perhaps mid to advanced sere--not climax range vegetation.

Great Sand Dunes National Park, Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No Kuchler unit because he mapped it as K-34 (Saltbush-Greasewood) when this is semidesert grassland within K-34. No SRM unit. Closest thing in Brown et al. (1998, p. 40) was Great Basin Shrub-Grassland 142.2, Mixed Bunchgrass-Shrub Series, 142.22 and that ain't it. Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

209. Miracles in the mountains- In late spring in the San Luis Valley with the Sangra de Cristo Range for a backdrop as a morning thunderstorm brought "showers of blessings" to a consociation of Indian ricegrass that formed a semidesert grassland. This Excellent condition range included amazingly few representatives of other grass species besides some widely scattered plants of squirreltail bottlebrush, needle-and-thread, and blue grama. There were also a scattered individuals of black greasewood, the dominant of desert scrub in alkali flats and local depressions in this area and a co-dominant with Indian ricegrass on savannas between alkaline desert and semidesert grassland. The main shrub on this range was apache plume (Fallugia paradoxa) a local patch of which was present in the second of these slides. There were also a few small plants of an unidentified species of rabbitbrush (Chrysothamnus sp.).

Pinyon pine (Pinus edulis)-juniper (Juniperus spp.) woodland was in the distant background up on the foot slope of the Sangra de Cristo Mountains.

Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No K unit because Kuchler did not map an Indian ricegrass unit. No SRM; no unit in Brown et al. (1998). They all missed it! Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

210. As grand a grassland as God ever grew, and in the desert- On the same day in late spring as shown in the preceding photographs skies cleared and the sun shone brightly on an Indian ricegrass semidesert grassland in the San Luis Valley with the Sangra de Cristo Range in the background. This was a different range from that shown in the preceding two slides though only about five or six miles down the road from that one This range was even more of a "pure" population (single-species stand) of Indian ricegrass than the one shown under a thunderhead.

There was need for but few words to describe this pristine, high-basin grassland. This consociation of Indian ricegrass shared the range with almost no other plant species except for a few widely scattered plants of rubber rabbitbrush (Chrysothamnus nauseosus) and the criciferous forb, sanddune or California wallflower (Erysimum capitatum). Indian ricegrass grasslands of this nearly single-species composition were reported by Tueller (1975, ps. 23-24) for arid conditions in the Great Basin Region.

If there was ever virgin range this was it. Simply an unbelieveable find. This spring and the preceding winter had been unusually wet so individual plants of Indian ricegrass were larger than typical, but no amount of moisture could have accounted for the immense size of these plants. They had unquestionably been managed for a number of years under light utilization. Root crowns of these plants were huge and these could only have grown to their immensity under the best of grazing management over a number of years. Size of individual plants was shown and described below.

Emphasis: this is native semidesert grassland. This was not a reseeding project.

Details of this superb specimen: Bureau of Land Management. The Foothills Allotment consisting of 7811 acres divided into three pastures. Total of 347 Animal Unit Months harvested between 1 June and 30 September by 93 head of cows (mixed breeding but black baldy sorts) with their calves. Administered out of the La Jara BLM field office. (Miss Melisa Shawcrost, persona communication).

Storm, sunshine, and sound range management showed what a semidesert grassland range can do if given the chance, but it takes all three.

Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No K unit because Kuchler did not map an Indian ricegrass unit. No SRM; no unit in Brown et al. (1998). They all missed it! Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

211. Details of a desert grass garden-Physiogonomy, structure, and botanical composition of the climax vegetation of a semidesert grassland range that was a consociation of Indian ricegrass. There were almost no other plant species present except for a few plants of rubber rabbitbrush and sanddune wallflower. In fact, the photographer had to search to find a local group of rabbitbrush plants. Instead a population of enormous Indian ricegrass plants formed a field-like natural grassland of almost unbelieveable purity. The remarkable size of these cespitose individuals was shown and described below.

Most of these bunchgrass clumps were made up of the same plant (one genotype) having many tillers, but perhaps some tufts consisted of shoots of several genetically distinct plants that germinated and emerged from rodent caches as documented by McAdoo et al. (1983). Either way, these large bunches had developed over several to many years and could only have reached such size under jucicious grazing management.

Bureau of Land Management, Foothills Allotment. Alamosa County, Colorado. Mid-June (late vernal aspect). FRES No. 40 (Desert Grasslands Ecosystem). No K unit because Kuchler did not map an Indian ricegrass unit. No SRM; no unit in Brown et al. (1998). They all missed it! Arizona/New Mexico Plateau- Sand Dunes and Sand Sheets Ecoregion, 22e (Chapman et al., 2006).

212. Indians' rice crop- Indian ricegrass on black greasewood-bunchgrass savanna (first photograph) and on an Indian ricegrass consociation of semidesert grassland (second photograph) in northern San Luis Valley. Cespitose habit of this bunchgrass was very noticeable. Also noticeable (if one can "read range sign") was the immense size of individual plants on semidesert grassland. Note for comparison the average size of a heap of cattle dung (typical "cow flop") in dead-center foreground of second slide. Some of these plants would have covered half of the flatbed of a one ton truck. Size of these plants growing in an arid (or, at least, nearly so) was on par with that of gigantic trees in rain forests.

Bureau of Land Management, Foothills Allotment. Alamosa County, Colorado. Mid-June.

213. Plants and a panicle- Portions of five plants of Indian ricegrass growing in a consociation of this species that comprised a semidesert grassland in northern San Luis Valley were presented in the first photograph. Second photograph was a part of a panicle of one of these plants showing the tremendously heavy grain crop produced in an extremely wet growing season. These plants and those shown in the immedately preceding photograph of the above pair of slides were giant specimens of their species growing on pristine (Excellent range conditin class) semidesert grassland that was made up almost exclusively of this one species.

Bureau of Land Management, Foothills Allotment. Alamosa County, Colorado. Mid-June, hard-dough phenological stage.

214. Ripening rice crop- Spikelets of Indian ricegrass on the widespread panicles typical of this species. Not typical was the extraordinarily heavy yield of grain that was produced in an unusually wet spring. Nonetheless, even with lower grain yield per plant or per unit of land there was such an extensive area of grassland dominated by Indian ricegrass and, as shown above, sometimes as exclusive single-species stands (consociations) that tremendous quantities of humanly edible grain could be gathered for food. This was the situation with regard to Indian ricegrass and American aborgines and, in fact, was origin of this common name.

Indian ricegrass, State Grass of Utah and Nevada, is one of the most valuable native grass species for reseeding degraded range and mined land (eg. reclamation of open surface coal mines). Unfortunately natural selection resulted in prolonged dormancy which usually has to be overcome by seed treatments such as chilling and scarification otherwise establishment efforts have often come to naught (Rogler, 1960). A good general guide to Indian ricegrass including stand establishment and cultivars was that prepared by Ogle (2000).

Bureau of Land Management, Foothills Allotment. Alamosa County, Colorado. Mid-June, hard-dough grain stage.

215. Striking crucifer of San Luis Valley grassland- Sanddune or California wallflower (Erysimum capitatum) on a local degraded area of Indian ricegrass semidesert grassland range at northern end of San Luis Valley. This is perhaps the most conspicuous--and strikingly so--forb of this range plant community. Large size, especially as to height, coupled with bright yellow petals sets this species off in an area of minimally diverse grasslands and savannahs. Hermann (1966, p. 12) suspected that this species might be a variety of E. asperum, a species grazed by all livestock species but that one of "negligible to slight" forage value.

Alamosa County, Colorado. Mid-June, peak standing crop and full-bloom stage.

216.. Shoot! Another plant of the same crucifer species- Another plant of sanddune wallflower provided closer-up shots of the sexual shoot of this conspicuous forb on Indian ricegrass-dominated semidesert grassland in the upper San Luis Valley. The indeterminate pattern of flowering (upward and outward sequence of blooming) was obvious with the siliques, crucifer fruits that are prominently elongated and considerably longer as, perhaps four to five times, than wide (Smith, 1977, ps. 66, 307). There are numerous Erysimum species throughout the Western Range Region, but E. capitatum is one of the more spectacular ones.

Alamosa County, Colorado. Mid-June, peak standing crop and full-bloom stage.