Miscellaneous Scrub Types

 

Sand Sagebrush (Artemesia filifolia) Range

1. Sand sagebrush (Artemesia filifolia) cover type- This is essentially a form of the sand bluestem- sand sagebrush grassland cover type but a reversal of these two dominants so as to be shrubland more than grassland. There are several intermediate gradations along this continuum that comprise the sand sagebrush savanna type. How much of the shrub dominance is potential natural vegetation and how much is retrogression (range deterioration) due to overgrazing and/or reduction of fire will likely always be contested. The denser populations of the more xeric Artemisia may be climax on the "tighter sites"(those with more clay content) and thus less favorable for sand bluestem, sand dropseed (Sporobolus cryptandrus), and plains lovegrass (Eragrostis intermedia). Potter County, Texas. June. Probably FRES No. 29 (Sagebrush Ecosystem) should include this range type as it has more sagebrush in its potential vegetation than FRES No. 39 (Prairie Ecosystem) which includes K-63 (Sand Sagebrush- Bluestem Prairie). SRM 722 (Sand Sagebrush-Mixed Prairie). Southwestern Tablelands- Semiarid Canadian Breaks Ecoregion, 26d (Griffith et al., 2004).

2. Sand sagebrush (Artemesia filifolia)- This is the major sagebrush species in the mixed prairie grasslands of the Southern Great Plains, both the Rolling Red Prairie (= Rolling Redlands, Redbeds) and High Plains (the Staked Plains or the Llano Estacado). In somewhat greater--though still naturally occurring-- densties or cover sand sagebrush forms a sagebrush mixed prairie savanna or sand sagebrush steppe (SRM 722). On overgrazed ranges and abandoned farmland (ie. "go-back land") sand sagebrush has become a major brush species on par with big sagebrush in the Intermountain West. At densities similar to those of pre-Columbian mixed prairie and sagebrush savanna (the best scientific estimates or "educated guesses") sand sagebrush is a highly desirable component of these ecosystems. It is not only a natural member of the biotic community filling an ecological niche, but it is valuable from such practical standpoints as providing some browse and substantial cover for big game species, furnishing emergency feed sources for livestock during prolongued periods of snow cover, and holding snow (ie. future soil water) that might otherwise blow off the land. Crowley County, Colorado. July.

3. Leaders of sand sagebrush (Artemesia filifolia)- Crowley County, Colorado. July.

Miscellaneous Forms of Big Sagebrush (Artemesia tridentata) Range

4. Big sagebrush-shrub steppe- As discussed in conjunction with Great Basin sagebrush desert, big sagebrush is a component of range cover types that vary from single-species stands to widely scattered plants in grasslands like those of the Palouse country. This scene in Hayden Valley, Yellowstone National Park is an excellent example of sagebrush vegetation included in an extensive unit mapped by authorities like Kückler as the generic "sagebrush type". The botanically rich understory of the community seen here includes bluebunch wheatgrass, Idaho fescue, blue grama, and buffalograss. Numerous composites "both forbs (e.g. Aster species) and low shrubs" comprise an obvious intermediate layer. July. FRES No. 30 (Sagebrush Ecosystem). K-49 (Sagebrush Steppe). SRM 314 (Big Sagebrush-Bluebunch Wheatgrass). Mixed Bunchgrass-Shrub Series in Great Basin Shrub-Grassland biotic community and with more sagebrush would be Sagebrush Series in Great Basin Desertscrub biotic community of Brown et al. (1998). MIddle Rockies- Yellowstone Plateau Ecoregion, 17j (Chapman et al., 2003).

5. Plains grassland and high desert blend in a broad ecotone with varying amounts of big sagebrush and various herbaceous communities depending on range site and past management practices. Here Wyoming big sagebrush (Artemesia tridentata wyomingensis), western wheatgrass, squirreltail bottlebrush, blue grama, sand dropseed, ect. form an obvious sagebrush shrub steppe. SRM description lacking: a big sagebrush-western wheatgrass type that should be with the SRM 314, 315, 316 series. Mixed Bunchgrass-Shrub Series in Great Basin Shrub-Grassland biotic community of Brown et al. (1998).

6. This general range type was noted variously by John E. Weaver and his colleagues, but less than 200 meters away in the same pasture of a BLM allotment was a western wheatgrass consociation form of mixed prairie on a clay soil under grazing by both cattle and white-tailed prairie dog (Cynomys leucurus).Such local variations in species composition across the range show why “expert opinion” as to role and density/cover of woody plants vary from expert-to-expert regarding almost any range cover type that could be interpreted as shrubland or shrub savanna. Moffat County, Colorado. June.FRES No. 29 (Sagebrush Ecosystem). At a larger scale the Kuchler unit is K-49 (Sagebrush Steppe) but most accurately it is a local example of K-50 (Wheatgrass-Needlegrass-[Sagebrush] Shrubsteppe).No specific SRM description, but similar to SRM 610 (Wheatgrass) or 607 (Wheatgrass-Needlegrass) (ie. Intermountain equivalent of the Great Plains type). Colorado Plateau- Semiarid Benchlands and Canyonlands Ecoregion, 20c (Chapman et al., 2006).

7. Profile of an alluvial soil supporting basin big sagebrush (Artemesia tridentata) illustrating that certain range plants can indicate the potential of soil or other factors for crop production. FRES No. 29 (Sagebrush Ecosystem). Another of several variants of K- 32 (Great Basin Sagebrush). SRM 401 (Basin Big Sagebrush). Sagebrush Series in Great Basin Desertscrub biotic community of Brown et al. (1998). Colorado Plateau- Semiarid Benchlands and Canyonlands Ecoregion, 20c (Chapman et al., 2006).

Mountain Big Sagebrush (Artemisia tridentata var. vaseyana) Range

8. *Mountain big sagebrush shrub steppe- Large-scale view of a shrub steppe dominated by mountain big sagebrush (Artemisia tridentata var. vaseyana= A. vaseyana) and with a grass understorey primarily of Idaho fescue and Sandberg bluegrass. The dominant forb was western false helleborne (Veratrum californicum). The cover of Artemisia was almost certainly excessive with a commensurate reduction in cover and productivity of the bunchgrasses so as to constitute range retrogression. This was yet another example of "Deserts on the March" with a mountain big sagebrush shrub steppe (a shrub savanna) having been (or in process of being) converted into a sagebrush shrubland approaching the climax big sagebrush cold desert of the Great Basin farther to the west in an arid zone. The species are the same in both climax range types but the relative proportions are "supposed to be" different, and they have become less so. This mountain big sagebrush-bunchgrass range was not so severely depleted-- not yet at least-- as to be an extreme departure from it's ecological (= successional) potential. Understorey species were still mostly those of climax shrub steppe with relatively little cheatgrass or downy brome (Bromus tectorum). From perspective of physiogonomy there was enough big sagebrush to indicate that it was a shrub steppe. (Ha!) *Technical note on taxonomy: Knight (1994, ps. 90-99 passim) discussed the sagebrush steppe of Wyoming, complete with inclusion of maps of eight species, in which he noted that "[m]ountain big sagebrush is found in the foothills at higher, cooler elevtions" (Knight, 1994, p. 91). Otherwise the most common A. tridentata taxon of the sagebrush steppe other than in alluvian basins was Wyoming big sagebrush (A. tridentata var. wyomingensis). Beetle (1960, p. 41) mapped the area in which the vegetation shown in these slides grew as A. tridentata subsp. vaseyana (note that Beetle used the taxon of subspecies rather than variety). Beetle (1960) did not recognize the taxon of wyomingensis. Weber and Wittmann (2001) noted presence of a subspecies of wyomingensis along the Colorado-Wyoming state line, but they interpreted the big sagebrush taxon of North Park as Seriphidium vaseyanum. Mutel and Emerick (1992, ps. 94, 103) used this latter species name. The current author designated the vegetation shown here as mountain big sagebrush, but noted that this A. tridentata var. vaseyana attained nothing of the stature or general large size of those individuals found in the foothills or up in the montane zone. Grand County, Colorado. June (most extreme drought for a one-year period in Colorado weather records). FRES No. 29 (Sagebrush Shrubland Ecosystem). K-49 (Sagebrush Steppe). Variant SRM 612 (Sagebrush-Grass). Southern Rockies-Sagebrush Parks Ecoregion, 21i, (Chapman et al., 2006).

9. Mountain big sagebrush-bunchgrass shrub steppe- General appearance of a shrub steppe having mountain big sagebrush as the dominant shrub (no other woody species were encountered) and the dominant species of this vegetation with an herbaceous layer of golden-aster or goldeneye (Heterotheca villosa= Chrysopsis villosa) and perennial bunchgrasses. The grasse species were also limited with Idaho fescue and Sandberg bluegrass the dominant and associate species, respectively. Western wheatgrass was the third-- a distant third-- major grass. It was nowhere common enough to add a sod-forming grass component. There was cheatgrass but at extremely infrequent occurrence. The golden-aster was in pre-bloom stage and not conspicuous, but many of the small grayish-green clumps are of this composite forb, and not bunchgrasses. This range was in some state of retrogression but not to the point that the species present were other than those of the climax. Proportions of bunchgrasses had probably declined while cover of the composites had increased, but the dominant grasses were still climax species and the cover and density of the Eurasian cheatgrass did not begin to approach the quantities associated with range depletion. This was appearance of the range following a grazing period in the driest growing season on record in Colorado. North Park, Jackson County, Colorado. June. FRES No. 29 (Sagebrush Shrubland Ecosystem). K-49 (Sagebrush Steppe). Variant of SRM 612 (Sagebrush-Grass). Mixed Bunchgrass-Shrub Series as an island disjunct from main body of Great Basin Shrub-Grassland biotic community of Brown et al. (1998). Colorado Plateau- Semiarid Benchlands and Canyonlands Ecoregion, 20c (Chapman et al., 2006).

10. Detail of mountain big sagebrush-bunchgrass shrub steppe- Close-up view of A. tridentata var. vaseyana- dominated range with golden-aster as the most common forb and Idaho fescue the dominant grass. In this worst drought on record in Colorado the Idaho fescue had gone dormant after completing it's annual cycle, but the golden-aster was pre-bloom stage. The flowering stalks of Idaho fescue are visible in immediate foreground by the sagebrush. North Park, Jackson County, Colorado. June. FRES No.29 (Sagebrush Shrubland Ecosystem). K-49 (Sagebrush Steppe). Variant of SRM 612 (Sagebrush-Grass). Mixed Bunchgrass-Shrub Series of Brown et al. (1998). Colorado Plateau- Semiarid Benchlands and Canyonlands Ecoregion, 20c (Chapman et al., 2006).

Dune Scrub

11. Climax Mesquite Sand Dunes- Coppice shrub from of mesquite. This soil is high in gypsum and various gypsophils are associates. Climax vegetation at edge of salt lakes This is one of the more unique vegetational cover types in the Trans-Pecos section of Basin and Range physiography. This dune land is hummocky with smaller dunes. Hudspeth County, Texas. June. FRES No. 33 (Southwestern Shrubsteppe Ecosystem). Subunit of K-53 (Trans-Pecos Shrub Savanna) too small to be mapped at Kuchler scale. SRM 729 (Mesquite); as the noted in SRM description this vegetation type "varies widely", and this is a "pure" form of scrub mesquite. Mesquite Series in Chihuhuan Desertscrub biotic community of Brown et al. (1998). Chihuhuan Deserts- Chihuhuan Basins and Playas Ecoregion, 24a (Griffith et al., 2004).

12. Alkali Sink Savanna- Alkali basins or sinks typically support shrubs or shrubs with an herbaceous understory dominated by grasses. Sometimes such basins are grasslands such as alkali sacaton flats, an example of which was included with the Grassland slides. On this same range site at the same location fourwing saltbush is co-dominant with alkali sacaton thereby forming an alkali sink grass-shrub savanna as seen here. Pale wolfberry (Lycium pallidum) is the major associate. This is a closed basin, gypseous soil (Dick-Peddie, 1993, p. 153) formed from a large gypsum deposit, the foredune (= dune front) of which is visible in the background. Gypsum is hydrous calcium sulfate, CaSO4 .2H2O, which exist as a colorless, white, gray, red, yellow, or brown transparent, monoclinic mineral (Morris, 1992) but which is rarely found in sand form because it is water-soluble. In the arid Tulorsa Basin there is not enough precipitation and surface runoff to  solubilize and carry the gypsum off.  It remains as a deposit. This vast gypsum dune field (the largest on Earth) formed when gypsum-bearing rain water and snowmelt ran off the surrounding Sacramento and San Andres Mountain ranges forming a vast lake in this part of the Tulorsa Basin. When the climate changed to a warmer, drier pattern the lake evaporated leaving the gypsum deposit. White Sands National Monument, Otero County, New Mexico. June. FRES No. 33 (Southwestern Shrub Steppe Ecosystem), one form or subunit of K-53 (Trans-Pecos Shrub Savanna), variant of SRM 701 (Alkali Sacaton-Tobosagrass). Saltbush Series in Chihunuan Desertscrub biotic community of Brown et al. (1998).

13. Gypsum Barrens or Gypsum Scrub- This is the dune front or foredune of the famed “white sands” of the Tulorsa Basin in southern New Mexico. This is actually “a vast gypsum sand area” (Dick-Peddiie, 1993, p. 128) with gypseous soils around its edges spreading out into an alkali sink. This huge gypsum “pile” occurs just above the alkali sink grassland vegetation dominated by alkali sacaton (included with the Grassland slides) and an alkali sacaton-fourwing saltbush-pale wolfberry savanna seen in the previous slide and at the base of the foredune (the alkali sacaton dominating the foreground of this photograph). Species on the foregune are soaptree yucca (Yucca elata) on the far left, fourwing saltbush in the center and rubber rabbitbrush (Chrysothamnus nauseosus) to the right of center. Gypsophiles or gypsophilous plants are those species which live or thrive in a gypsum-rich soil (Morris, 1992).  All of the gypsum-dwelling species found here are widely distributed ones which more commonly thrive on non-gypseous soils. This suggests that the ones growing on this gypsum-rich habitat are unique gypsophilous ecotypes of species that are not usually gypsum-adapted plants. White Sands National Monument, Otero County, New Mexico. June. FRES No. 33 (Southwestern Shrub Steppe Savanna), one form or subunit of K-53 (Trans-Pecos Shrub Savanna) for the alkali sink vegetation and no K-unit for the foredune scrub. SRM 701 for the alkali sacaton-fourwing saltbush savanna but no SRM for the unique gypsum scrub (too many  shrubs for SRM 701).

14. Gypsum Desert Dune Scrub- This scrub vegetation on the gypsum foredune is a remarkably diverse range community in a small area. It is the point at which gypsum foredune meets the alkali basin or sink of alkali sacaton. The immediate foreground is dominated by alkali sacaton and soaptree yucca, the latter also extending up the lower and mid portions of the foredune. Rubber rabbitbrush and fourwing saltbrush occupy the mid-elevation of foredune while the top of the foredune (center ridgeline) supports skunkbush sumac (Rhus trilobata= R. aromatica). These are probably gypsophilous (adapted or surviving on gypsum-habitats) ecotypes. This vegetation is growing on a foredune on a less xeric and cooler east side. This is an example of the importance of aspect, the position facing a particular direction usually expressed as a compass direction in degrees or cardinal directions of north, south, east or west or breakdowns thereof such as a southeast or northwest aspect (Helms, 1998) or, more simply, the direction the slope of a hill or mountain faces as in a north-facing aspect (Morris, 1992). Influence of aspect is more commonly thought of as being important in the mountains, but this example illustrates that aspect can be just as much an abiotic factor at smaller scale in deserts.  White Sands National Monument, Otero County, New Mexico. July. FRES No. 33 (Southwestern Shrub Steppe Ecosystem), but no K-unit or SRM description fits the gypsum dune shrubland.

15. Dwarf Rio Grande cottonwood on Gypsum Scrub Barrens- This part of the foredune is populated by Rio Grande cottonwood (Populus deltoides subsp. wislizenii). This is a subspecies of the eastern cottonwood which is so common on the eastern prairies (eg. the State Tree of Kansas). Such depauperate cottonwood trees are of limited browse value but they were  shown to impress upon the student the importance of speciation and ecotypic variation as an expression of natural selection. White Sands National Monument, Otero County, New Mexico. June. FRES No. 33 (Trans-Pecos Shrub Steppe Ecosystem), but no K-unit or SRM designation for this unique desert dune scrubland vegetation.

16. Beauty in the grotesque and the gypsum- Shoot of a mature Rio Grande cottonwood on the gypsum dunes of the enchanting Tularosa Basin of central New Mexico. An individual of the unique gypsum dunes ecotype of one the major Populus species in North America. The twisted, dwarf trunk of this "runt" cottonwood provided a good example of ecotypic variation and natural selection to a unique and very harsh habitat. Live on little tree: you teach a good lesson. White Sands National Monument, Otero County, New Mexico. June.

17 Gypsum Desert Scrub- This is the interior of the immense gypsum dune barrens in the Tulorsa Basin of southern New Mexico. This is inside a barchan dune in the interior of the extensive gypsum dunefield. The large cespitose grass in the foreground is gyp (for gypsum) dropseed (Sporobolus nealleyi). The shrub immediately behind it on the near crest of the barchan dune is rubber rabbitbrush and the dark green shrubs in the background (the choppy dunes of the foredune crest) are skunkbush sumac. Gyp dropseed is another example of speciation as an adaptation to unique abiotic environments

Comparison of this immediate habitat with the alkali sink savanna (and the alkali sink grassland in the Grassland slides) illustrates vividly the concept of ecological niche and Gauses Competitive Exclusion Principle that no two species can occupy the same ecological niche. Sporobolus airoides dominates the alkali sink immediated adjacent to the gypsum dune fields while S. giganteus and S. wrightii form  sacaton swales or flats in this same area but on non-gypseous, less-saline soils (cf. Grassland slides for these grassland range types). Mesa dropseed (S. flexuosus) is an associate species on climax black grama semidesert grasslands and a dominant increaser on deteriorated black grama ranges that are in immediate or close proximity to all these range sites/plant communities. Also refer to the true prairie and tallgrass prairie range types (Grassland slides) for dominance by prairie dropseed (S. heterolepis) and tall dropseed (S. asper). The Sporobolus species may not rival the speciation of Darwin’s finches but these diverse bunchgrasses illustrate the concept of “fitness” (natural selection for those taxa whose genes are passed to the most progeny).

Winterfat (Eurotia lanata= Ceratoides lanata) Range

18. Winterfat (Eurotia lanata) scrub- A consociation of this valuable browse species is another major form or section of Great Basin Desert. It is excellent winter range particularly for domestic sheep (Ovis aries), mule deer (Odocoileus hemionus), and pronghorn (Antilocapra americana). Single-species stands such as this one provide quality winter range, but frequently have been overbrowsed. Southern Utah. December. No Kuchler unit for this form ofFRES No. 30 (Sagebrush Ecosystem), but it is likely be a variant of K-32 (Great Basin Sagebrush). Winterfat variant of SRM 414 (Salt Desert Shrub). Winterfat Series in Great Basin Desertscrub biotic community of Brown et al. (1998).

Black Greasewood (Sarcobatus vermiculatus) Range

19. Greasewood-saltgrass shrubland- Saline sink in North Park of the Southern Rocky Mountains with a shrub overstorey comprised exclusively of black greasewood (Sarcobartus vermiculatus) and an inland saltgrass-dominated understorey accompanied with isolated individuals of threadleaf sedge (Carex filifolia). This depression usually has standing water for a period during spring after which the soil water content remains relatively high on the low permeability soil. This both supplies adequate water for greasewood and dilutes the salt concentration in the soil of this small basin thereby reducing salt stress to plants. As with most members of the Chenopodiaceae, greasewood posses salt-extruding glands that prevent salt toxicity. These photographs were taken during the single driest growing season to-date in Colorado weather records (2002) and the greasewood, which is not well-adapted to prolongued drought, showed drought stress as did the graminoids. It was not known whether the cover of greasewood was excessive and was a brush problem due to mismanagement (perhaps an increase in shrub density, cover, etc. with past overgrazing maybe even tracing back to the open range era) or if this was the ecological potential or climax vegetation. Certainly enough has been learned to identify or "map" this as a naturally Sarcobatus vermiculatus-dominated shrubland with a saltgrass understorey. This vegetation was described by Knight (1994, ps. 108-113). Franklin and Dyrness (1973, ps. 227, 245) designated this community the Sarcobatus vermiculatus/ Distichlis stricta association of shrub steppe in the Columbia Basin of eastern Oregon and Washington. The climate under which this range type developed was semiarid and the composition of the plant community was such that this was semidesert shrub steppe and not a cold desert saltbush-greasewood scrub. An example of that community on the Red Desert of Wyoming-- and not in a drought-- was presented under the Great Basin Desert portion here in the Shrubland section. The range plant community shown here was one range cover type among several of the Rocky Mountain scrub or "soft chaparral". Arapaho National Wildlife Refuge, Jackson County, Colorado. North Park. June. No appropriate FRES or Kuchler designations because those units were too large for this vegetation, but this was a legitimate range cover type of shrub steppe. This was another example of the incompleteness-- and need for on-going research into-- vegetation mapping and classification. In the author's judgment this was climax or potential natural vegetation. Franklin and Dyrness (1973, ps. 227, 245) clearly designated it (the black greasewood-inland saltgrass association) as natural vegetation. It is definitely the black greasewood shrub steppe and on equivalent ecological standing with the big sagebrush shrub steppe. It has yet to be designated and described. One important function of technical writing is to point out deficiencies or "missing pieces" in the existing literature. That was just done here. Variant of SRM 414 (Salt Desert Shrub). Southern Rockies- Sagebrush Parks Ecoregion, 21i (Chapman et al., 2006).

20. Black greasewood-Sandburg bluegrass range- In a transition zone between the High Lava Plains and Basin and Range Provinces (Franklin and Dyrness, 1973, p. 6) this upper storey consociation of black greasewood and understorey of Sandberg bluegrass (Poa secunda= P. sandbergii) formed a relatively simple plant community that afforded range for both livestock and big game-- inhospitable and unappealing as it might appear to human senses. As cited in the preceding caption, Franklin and Dyrness (1973, ps. 227, 245) designated a black greasewood-inland saltgrass community for central and eastern Oregon. These workers made no reference to a greasewood-Sandberg bluegrass community or variant of the former community, but that was clearly the vegetation presented here. In fact, this photographer observed no saltgrass on the range portrayed here. Rather Sandberg bluegrass held forth as essentially the only graminoid species. There was some scattered cheatgrass (Bromus tectorum) but it would rank a weak associate species. (Refer to two slides immediately below.) Neither were Carex species encountered on this range in this typical precipitation year. Malheur National Wildlife Refuge, Harney County, Oregon. June. Estival aspect. FRES No. 30 (Desert Scrub Ecosystem) but no appropriate Kuchler unit for natural plant communities of this scale. Kuchler unit 34 (Saltbush-Greasewood) is "as close it gits" and that does not reflect those plant communities that are greasewood consociations. Furthermore, the description of this unit (Kuchler, 1964, unit 40 therein) included no grasses or grasslike plants. Kindly note again comment on incompleteness of vegetation designations and mapping given in preceding caption. SRM 414 (Salt Desert Shrub). Northern Basin and Range- Dissected High Lava Plateau Ecoregion (Thorson et al., 2003).

21. Species composition of black greasewood-Sandberg bluegrass range plant community- In addition to the dominant shrub and herbaceous species a specimen of cheatgrass was represented in this photograph. Cheatgrass was widely scattered and a search was necessary to find cheatgrass and the dominants within the same "frame". Transition zone between High Lava Plains and Basin and Range provinces (Franklin and Dyrness, 1973, p. 6), but this range vegetation clearly had physiogonomy, structure, composition more that of the Great Basin Desert than of a shrub steppe, the major expression of vegetation in this area. Malheur National Wildlife Refuge, Harney County, Oregon. June. FRES No. 30 (Desert Scrub Ecosystem) but no apt Kuchler unit (K-34 was "closest fit"). SRM 414 (Salt Desert Shrub). Northern Basin and Range- Dissected High Lava Plateau Ecoregion (Thorson et al., 2003).

22. Sandberg bluegrass- Mature (seed-ripe stage) Sandberg bluegrass in understorey of black greasewood-dominated scrub range. Although this range vegetation was at extreme northern edge of the Great Basin (more as an "island" thereof) it was reasonable typical of the Great Basin Desert type. Malheur National Wildlife Refuge, Harney County, Oregon. June.

Mountain mahogany (Cercocarpus spp.) Scrub

In various western mountain ranges, especially those of the Intermountain West, various species of mountain mahogany are major, often dominant, shrubs. Mountain mahogany species occupy niches as important browse species on grasslands, savannas, and forests. For instance, true mountain mahogany (C. montanus) often comprises a shrub layer in ponderosa, western yellow, pine (Pinus ponderosa). This range type was treated under the Woodlands and Forests biome in the chapter entitled Northern and Central Rocky Mountain Forests. On drier mountain slopes such as on ranges in the Great Basin a unique scrubland dominated by curl-leaf mountain mahogany develops at elevations just above the pinyon pine-juniper woodland zone. The relatively restricted curlleaf mountain mahogany shrubland, SRM 415 (Curlleaf Mountain Mahogany), was regarded by the current author as being of such patchy and limited spatial occurrence that it was included as a miscellaneous scrub type. SRM 415 was also included in the Intermountain Forest chapter wherein it can be studied with conterminous zones of forest range communities.

23. Upper elevation of Upper Sonoran Life Zone- Curl-leaf mountain-mahogany (Cercocarpus ledifolius) shrubland was the range vegetation at the highest elevation of the Upper Sonoran Life Zone in the Snake Mountains. These two landscape-scale photographs depicted characteristic curl-leaf mountain mahogany scrubland in the Snake Range relative to zones (= belts) of range plant communities in these mountains. Zonal range vegetation was determined to large extent by factors (precipitation, temperture, soils, degree of slope, winds, etc. ) associated with differences in elevation and, to lesser degree, direction of slope (eg. north, south, west slopes). Distant range vegetation that was dark green in color was tree-dominated range plant communities. That which was below (lower in elevation) this mountain-mahogany belt were various communities dominated by singleleaf pinyon pine and juniper (primarily Utah juniper). Natural plant communities above this zone of mountain mahogany scrub (higher in elevation) were vrious forest cover types (ponderosa pine-Douglas-fir, quaking aspen, Englemann spruce, limber pine, and bristle cone pine). The bare area on the distant mountain, which was Wheeler Peak, was the alpine range ecosystem above timberline. Some of the curl-leaf mountain-mahogany plants were of heights (as tall as 15-25 feet) more typical of trees than shrubs, but almost all such plants were of the multi-stemed habit characteristic of shrubs. This woody plant-dominated (based on canopy cover, physiogonomy, plant height) vegetation was therefore defined precisely as shrubland or scrub and not woodland. There was one-- sometimes two-- layer(s) lower layers of plants. Shrubs that were relative common in lower woody layer(s) included low sagebrush (which was the understorey dominant in the adjacent and lower Utah juniper-low sagebrush range community), viscid rabbitbrush, hairy golden aster, and fringed sagebrush (Artemisia frigida). Composites were clearly "in control" of lower shrub layer(s). The herbaceous layer of this range vegetation was dominated by muttongrass of Fendler's bluegrass. The associate herb was the range forb, lanceleaf phacelia (Phacelia hastata= P. leucophylla). Many of the same range forb species grew on this belt of mountain-mahogany scrub range and the adjacent zone of Utah juniper-low sagebrush-grass range. Great Basin National Park, White Pine County, Nevada. June, estival aspect. Elevation was roughly 8,000 to 8,500 feet up to as high as 9,000 feet on dry south and west slopes. FRES No. 34 (Chaparral-Mountain Shrub Shrubland Ecosystem). K- 31 (Mountain-mahogany-Oak Scrub), mountain-mahogany variant thereof. SRM 415 (Curlleaf Mountain Mahogany). Mountain-Mahogany Series 132.12 of Great Basin Montane Scrub 132.1 of Brown et al. (1998, p. 39). Cercocarpus ledifolius Shrubland Alliance is as far as can go because National Vegetation Classificatioin for Nevada (Nevada Natural Heritage Program, 26 September, 2003) did list a community (association) of this composition. Central Basin and Range- Carbonate Woodland Zone Ecoregion, 13q (Bryce et al., 2003).

24. Scrub range in the Snake Range- Interior of the curl-leaf mountain-mahogany-low shrub-muttongrass scrubland range presented in the two immediately preceding photographs. The multi-stemmed habit of mountain-mahogany plants was pronounced. Herbaceous and woody layers in the understorey of this range vegetation varied greatly at local (microclimate) scale. Single species of plants tended to form local populations or colonies (Clements, process of aggregation or "birds of a feather flock together"). This was particularly so for lanceleaf phacelia and muttongrass. Perhaps this was a combination of plant dispersal characteristics and considerable vriation in edaphic habitat at scale of microsites. Several plants of fringed sage were noticable in foreground of both photographs. Great Basin National Park, White Pine County, Nevada. June, estival aspect. Elevation was approximately 8,000 to 8,500 feet up to 9,000 feet on south and othr dry slopes. FRES No. 24 (Chaparral-Mountain Shrub Shrubland Ecosystem). K-31 (Mountain-mahogany-Oak Scrub), "pure" mountain-mahogany variant thereof. SRM 415 (Curlleaf Mountain Mahogany). Mountain-Mahogany Series 132.12 of Great Basin Montane Scrub 132.1 of Brown et al. (1998, p. 39). Cercocarpus ledifolius Shrubland Alliance is "it" because there was not an association level in National Vegetation Classification for Nevada (Nevada Natural Heritage Program, 26 September, 2003) having this composition. Central Basin and Range- Carbonate Woodland Zone Ecoregion, 13q (Bryce et al., 2003).

25. Curlleaf mountain-mahogany (Cercocarpus ledifolius)- Typical plant of this shrub species in the Snake Range of the Great Basin. Description of this species as to browse value was in the Range Plant Handbook (Forest Service, 1940, B50) as well as Dayton, 1931, p. 45) and Sampson and Jespersen (1963, ps. 80-81). See also Lanner (1984, ps.180-182) for a brief natural history. Snake Range, Great Basin National Park, White Pine County, Nevada. June, pre-bloom stage..

26. Curlleaf mountain-mahogany - Typical columnar habit of curlleaf mountain mahogany. According to Dayton (1931, p. 45) this is probably the largest and most treelike of the Cercocarpus species. In addition, it has evergreen leaves which increase it's browse value during winter months. Rock Canyon, Utah County, Utah. June.

27. Leaders of curlleaf mountain mahogany- Bark and leaves of curlleaf mountain mahogany. Rock Canyon, Utah County, Utah. June. C. montanus and C. ledifolius were described in the various editions of North American Range Plants (Stubbendieck et al., 1981, 1982, 1986, 1992) and the Range Plant Handbook (Forest Service, 1940, B49-B51) as well as miscellaneous state and regional references on browse plants such as for California (McMinn, 1939, ps. 205-209; Sampson and Jesperson, 1963, p. 78-81) and eastern Oregon and Washington (Hayes and Garrison 1960, ps.178-180).

28. Muttongrass, Fendler's bluegrass, or mutton bluegrass (Poa fendeleriana)- This delightful festucoid grass was the dominant herbaceous species on a curl-leaf mountain-mahogany scrubland range.Muttongrass (descriptive common name for value of this species as sheep forage) is one of the most important of all bluegrasses on the Western Range. A valuable practical description of muttongrass was provided by the Range Plant Handbook (Forest Service, 1940, G100). This remarkable species ranges from the Chisos Mountains of Trans Pecos Texas to British Columbia. Muttongrass has deservedly been on the Society for Range Management "200 list" for the Intercollegiate Range Plant Contest. These fine specimens were in the understorey of a curl-leaf mountain-mahogany scrub range (on which it was the dominant herbaceous species). Snake Mountains, Great Basin National Park, White Pine County, Nevada. June, grain-ripe stage.

29. Panicles of muttongrass- Panicles with large spikelets of full of ripe grain in Poa fendeleriana. Spikelets of muttongrass are some of the largest of any bluegrass species in North America. Fendler's bluegrass is a major range forage species in the mountains of the Great Basin. Snake Range, Great Basin National Park, White Pine County, Nevada. June, "seed-ripe" phenological stage

Breaks Scrub Within major land regions there are frequently abrupt and pronounced topographic departures from the prevailing physiography or "lay of the land". These include local changes in landscape such as bluffs, cliffs, deep draws, and natural drainages like arroyos as well as extensive or far-reaching abrupt land surface changes such as escarpments, canyons, and gorges. Such prominent abrupt deviations in land surface, plane topographic distinctions, are especially obvious where vegetation is less dense and/or vistas are larger (eg. grasslands, deserts). Abrupt changes in the land surface of regional (= zonal) climax vegetation (= plant formations) often result in differences in range plant communities within relatively short distances or small areas. Given the critical importance (hence, attraction) of water to all life, riparian vegetation is perhaps the most conspicuous of these "short-distance" spatial changes between local and regional or zonal vegetation. Vegetation like gallery forest is especially conspicuous in the "sea" of vast grasslands. Another prominent-- though less conspicuous to most human viewers-- topographic departure on the prevailing rolling and, especially, flat land surfaces of grasslands is the geologic feature known as breaks. Breaks (always written and spoken of in the plural) is a general term used to denote a sudden or pronounced change in topography especially as from plains to hilly terrain. Abrupt changes in land surface features designated as breaks can be local as, for example, one small hill or mesa (or one side or face thereof) or extensive such as an escarpment extending along a geological feature (eg. Missouri Breaks along the Missouri River). Within the Great Plains province there are breaks of varying dimensions and location ranging, again, from relatively small and local to expansive and general within a larger area. In Range Management these breaks-- regardless of spatial scale-- typically designate breaks range sites. In fact, there are several different breaks range sites. Breaks often (perhaps typically) support potential natural vegetation that is different from that of the surrounding regional climax due to the unique-- in particular, physical and chemical-- features of breaks. The distinctive habitats of breaks can support range vegetation that is either preclimax or postclimax in relation to prevailing zonal vegetation (regional climax) when viewed by monoclimax theory. From perspective of polyclimax theory breaks are edaphic, topographic, etc. climaxes. Recognition of breaks range sites was probably an outgrowth (and acceptance) of the polyclimax view, but breaks can be understood as both pre- and postclimax communities and/or as edaphic or topographic climaxes. In some instances the different and distinctive breaks range vegetation can be explained relative to fire or grazing. In these instances pyric and zootic impacts have been and still are less influencial than on surrounding vegetation due to an inherent protection. Most species of herbivores (native or domestic) are less apt to frequent the steep land of breaks. Fires are often less apt to burn breaks due to paucity of fine fuels or biomass (this lower productivity in turn a result of less soil water as a consequence of greater rate of runoff and shallower soils). Conversely, vegetation on steep slopes can burn-- when it does burn-- at greater intensity under an upslope head fire. Likewise, when grazing/browsing does occur the range may be harmed to a greater degres by damage to steep slopes and defoliation of plants growing on harsher sites. Either way (or both ways) breaks range plant communities often differ drastically from adjacent vegetation. This difference is often greater cover, density, etc. of woody plants. Again this may be due partly to protection from, say, fire or, alternatively, disturbance-induced retrogression caused by hotter fires or more grazing/browsing action. In cases of east and, especially, north slopes the habitat, the range site, is more mesic and generally supports greater water-requiring plant species. These tend to be woody species that are deeper-rooted but often at competitive disadvantage to shallower-rooted herbaceous plants that are more efficient at rapid absorption of soil water. Breaks often serve as reserviors of tree and shrub species whose propagules can invade surrounding vegetation in absence of normal fire regimes (underburning), with grazing damage (overgrazing in particular), under short and intense atmospheric abberations (drought typically being Number One on range), or with major long-term changes including climatic shifts such as global warming (or cooling). Badlands and canyonlands are some of the larger and better-known examples of land forms having breaks. These often have extensive networks of breaks above a series of valleys and interconnecting channels. The largest of such land forms in the Southern Great Plains is the Caprock Excarpment where the Ogalla Formation-capped High Plains (Staked Plains or Llano Estacado) break off onto the Red Hills (known in Texas as the Rolling Red Plains and in Oklahoma as the Redbeds Plains). This geologic feature or general terrain is the "breaks of the plains" (Fenneman, 1931, p. 28-30; Fenneman, 1938, ps. 606, 618-620)). This large geologic feature includes other range sites besides breaks sites. Within the Great Plains region there are countless breaks occurring at local scale. Examples of local breaks and those of the Caprock canyonlands were presented below.

30.. Plains breaks- Local breaks in overall mixed prairie range in the Rolling Red Plains region. A steep north slope below a grama grass-buffalograss-threeawn mixed prairie supported two distinct range plant communities. Upper slope (above the land slump) was a stand of redberry juniper (Juniperus pinchotii) with an understorey of short and mid-grass species. This shrubland was a downslope extension of mixed prairie range from the upland above. (This Rolling Red Plains mixed prairie vegetation was presented in the Grasslands, Mixed Prairie portion of this publication). Below the landslide was a species-diverse community that had developed a moist drainage. In the horizonal photograph a southwestern black willow (Salix gooddingii) was growing in far left foreground with scattered skunkbush sumac and young netleaf hackberry (Celtis reticulata) above and to right of the willow. The shrub with twining or twisted aerial branches at right midground was pale honeysuckle (Lonicera albiflora var. dumosa). There was a robust individual of sand bluestem in center foreground accompanied by sand sagebrush. Other grass species included little bluestem, sideoats grama, and plains bristlegrass (Setaria leucopila). The vertical slide displayed in greater detail the center portion of this slope transect. Panicles of a specimen of naturalized Johnsongrass (Sorghum halepense) was visible in extreme left foreground of this second slide which demonstrated-- as was often the case in this publication-- the adaptability of this introduced, often weedy, perennial sorghum. Dickens County, Texas. August; estival aspect. Localized shrubland range community within FRES No. 38 (Plains Grasslands Ecosystem). Too small to be mapped by Kuchler unit but lower plant community perhaps could be viewed as local variant of K-62 (Bluestem-Grama Prairie). Successional status of juniper-dominated community was uncertain and there seemed no obvious Kuchler unit. Variant of SRM 718 (Mesquite-Grama) or of 727 (Mesquite-Buffalograss) fit juniper shrubland. SAF 66 (Ashe Juniper-Redberry [Pinchot] Juniper). Rough Breaks range site. Southwestern Tablelands- Caprock Canyons, Badlands, and Breaks Ecoregion, 26c (Griffith et al., 2004).

31. Plains breaks- Another "plot" of a north slope Rough Breaks range site below an upland of Rolling Red Plains mixed praire range (this latter presented in Grasslands, Mixed Prairie herein). A redberry juniper-dominated mid-grass and short grass range community grew on the upper reaches of this slope above the slump and eroded portion. The lower plant community had a zone-like arrangement of species with sand sagebrush and lotebush (Ziziphus obtusifolia) in the immediate foreground with a hardy plant of sand bluestem "for good measure". The most common species that formed a large thicket immediately behind the "zone" just described was skunkbush sumac. In the midst of this thicket was a conspicuous forked-trunk mountain mahogany (Cercocarpus montanus), the largest, tallest shrubin right-center foreground. Small patches of sand plum (Prunus gracilis) occurred behind the skunkbush thicket. Upslope, little bluestem, sideoats grama, and plains bristlegrass grew scattered but to large size. Interestingly, there was mesquite at this location. Dickens County, Texas. August. Estival aspect. Localized shrubland range community within FRES No.38 (Plains Grasslands Ecosystem). Too small to carry Kuchler unit. SAF 66 (Ashe Juniper-Redberry [Pinchot] Juniper). Redberry juniper vriant of SRM 727 (Mesquite-Buffalograss) perhaps most apt for the upper plant community though SRM 718 (Mesquite-Grama) was about as appropriate, except as noted at end of last paragraph there was no mesquite on this local Rough Breaks range site. Southwestern Tablelands- Caprock Canyons, Badlands, and Breaks Ecoregion, 26c (Griffith et al., 2004).

32. Caprock canyonlands- View over Caprock or Llano Estacado Escarpment, "the break of the plains" where the High Plains (= Staked Plains or Llano Estacado) breaks over on the Red Hills (most commonly designated Rolling Red Plains in Texas). Here prominent landscape features include dissected plains, canyon slopes and ridge tops each of which has it's own characteristic plant community. Also visible in this and several of the following slides are the three major geologic formations comprising the High Plains beginning with the upper or most recent: 1) Ogalla, 2) Dockum sandstone groups (Tecovas and Trujillo), and Permian Redbeds (of several formations). It is estimated that this entire time frame spanned from 200 to 300 million years ago. What a memory God must have! Shrubs in the foreground were honey mesquite while redberry juniper populated canyon sides in midground. Dominant grasses were little bluestem and sideoats grama. This was likely the potential natural vegetation: SRM 718 (Mesquite-Grama). Canyon sides: SAF 66 (Ashe Juniper-Redberry [Pinchot] Juniper). Southwestern Tablelands- Caprock Canyons, Badlands, and Breaks Ecoregion, 26c (Griffith et al., 2004). Caprock Canyons State Park, Briscoe County, Texas. August.

33. Canyonlands range- Climax vegetation on ridge tops and canyon slopes of the Caprock Escarpment. These two views were on edges of ridge tops peering over canyon slopes down into the dissected plains of the break between the High Plains and Red Rolling Plains of the Great Plains physiographic province. The clock of geologic time can be read in these Texas canyonlands or badlands. Range vegetation (dominance types) on the ridge tops was comprised of sideoats grama, feather dalea (Dalea formosa), redberry juniper, soapweed yucca (Yucca glauca), hairy grama (Bouteloua hirsuta), blue grama (B. gracilis), and silver bluestem (Andropogon saccharoides= Bothriochloa saccharoides). It was designated and mapped by Wester (undated) as the RedberryJuniper-Oak-Feather Dalea-Hairy Grama-Sideoats Grama Community Complex. In the second slide another dominant range shrub, little sumac (Rhus microphylla) was presented at far left foreground. In this habitat fire frequency was historically low on canyon sides and of low intensity on ridge tops due to obvious limited biomass for fuel and, especially finner fuels for initiation of fire.All these spceies resprout readily even the redberry juniper (sprouting is of course rare in conifers). Caprock Canyons State Park, Briscoe County, Texas. August. Estival aspect; peak standing crop for mid- and short grasses. FRES and Kuchler designations did not exist for this range vegetation. Although this beautiful-- if relatively unproductive-- landscape was extensive it was smaller than mapping units of standard plant formations. SAF 66 (Ashe Juniper-Redberry [Pinchot] Juniper). SRM rangeland cover type was likely some variant of SRM 718 or 727. Range sites readily discerned were Hardland Slopes on ridge tops and part of upland mixed prairie and Rough Breaks down on canyon slopes below ridge tops. Southwestern Tablelands- Caprock Canyons, Badlands, and Breaks Ecoregion, 26c (Griffith et al., 2004).

34. Sample of canyonlands vegetation- Feather dalea with silver bluestem to it's left and soapweed yucca behind were typical example of species dominant or common on ridge tops of Rolling Red Plains canyonlands. Caprock Canyons State Park, Briscoe County, Texas. August.

35. Feather dalea (Dalea formosa)- One of the dominant species on ridge top positions on Caprock Escarpment. Grass was silver bluestem, a mid-grass species.Caprock Canyons State Park, Briscoe County, Texas. August.

36. Close-up of feather dalea- Leaders and leaves of a dominant shrub of one of several range plant communities growing on the canyonlands of the Caprock Escarpment. Caprock Canyons State Park, Briscoe County, Texas. August.

37. Canyonlands State Grass- Sideoats grama (Bouteloua curtipendula), State Grass of Texas, on a ridge top of the Caprock Escarpment at hard-grain stage. Caprock Canyons State Park, Briscoe County, Texas. August.

38. Littleleaf sumac (Rhus microphylla)- Main branch of a dominant shrub on ridge tops of Lland Estacado (= Caprock) Escarpment canyonlands. This shrub furnishes highly palatable browse. Caprock Canyons State Park, Briscoe County, Texas. August.

39. Branches of littleleaf sumac (Rhus microphylla) in full-fruit- Leaders of littleleaf or desert sumac (first photograph) and details of leaves and fruit of the same (second slide). The fleshy fruit of Rhus species is a drupe: the fruit type in which the outer layer or skin is the exocarp, the fleshy layers are mesocarp, and the bone-like seed coat is the endocarp; endocarp and seed constitute a pyrene (the stone or pit). Hence, drupes are stone fruits or pit fruits (Smith, 1977). This woody species is well-adapted to xeric environments and is widely distributed on harsher habitats such as drier or shallower soils in the Great Plains as well as basins and bajadas of the Chihuhuan Desert. Desert sumac is often common of tobosagrass (Hilaria mutica) swales or "flats" in the semidesert grasslands. Drupes are sometimes cooked in hot water to make "hillbilly lemonade". Beats a job in the eye, but this author recommends the "real stuff" (or tea or coffee or milk or cold water or ...; you get the picture). Davis Mountains, Brewster County, Texas. June.

Sandrough Scrub

40. In addition to the major shrublands of coastal and mountain chaparral and deserts there are numerous local kinds of vegetation dominated by and made up largely of shrubs due to unique habitat features like soil, topography, water table, and so on. Riparian vegetation falls into this category as does that of deep sand or water drainage like seeps that support vegetation more mesic than that of the region in which it occurs. Ecologists like Fredric Clements labeled such vegetation as postclimax. An example of a local postclimax range vegetation type in the Texas Cross Timbers is sandrough, stunted, or dwarf forms of post oak, blackjack oak, western hackberry (Celtus occidentalis) with such associates as greenbriar (Smilax spp.) and lime prickly ash, tickletongue, or toothache-tree (Zanthoxylum hirsutum). Here sandrough is growing on a deep sand range site. Erath County, Texas. October, autumnal aspect. Sandrough fits in FRES No. 15 (Oak-Hickory Ecosystem), K-75 (Cross Timbers), but it is a shrub form of it. No SRM type description; an edaphic variant of SRM 732 (Cross Timbers, Texas; Little Bluestem-Post Oak). Edaphic variant of Limestone Cut Plain Cross Timbers Ecoregion, 29e (Griffith et al., 2004).

41.. Although frequently misinterpreted as a woody invasion of deteriorated range, sandrough is an edaphic climax. Thus while it is a minor range type it provides an example of the variation in vegetation that exist within regional or zonal scale climaxes. It is but one example of the sort of plant community that fueled the debate between monoclimax and polyclimax theories of vegetation. Of the few herbaceous understory species in sandrough, sand lovegrass is dominant. Erath County, Texas. October, autumnal aspect. Scrub variant in K-75 (Cross Timbers). Edaphic variant of SRM 732 (Cross Timbers, Texas; Little Bluestem-Post Oak) Edaphic variant of Limestone Cut Plain Cross Timbers Ecoregion, 29e (Griffith et al., 2004).

42. Inside sandrough- Interior of a sandrough dominated by post and blackjack oak. Erath County, Texas. April, vernal aspect. Even deep in interior of this edphic climax scrubland there are frequently herbaceous species including sand lovegrass (Eragrostis trichoides), and little bluestem. A dominant forb was spiderwort (Tradescantia subacaulis). Also present, especially on primeter, were mustang grape (Vitis mustangensis) and rough-leaf dogwood (Cornus drummondii). Scrub vriant of K-75 (Cross Timbers). Edaphic variant of SRM 732 (Cross Timbers, Texas; Little Bluestem-Post Oak). Edaphic variant of Limestone Cut PlainCross Timbers Ecoregion 29 e (Griffith et al., 2004).

43. Sand lovegrass (Eragrostis trichoides) on a Cross Timbers sand rough- This is the climax dominant grass on the deep sandy soils that support the scrub oak form of Cross Timbers or, more precisely,. the deep sand oak shrubland of the Texas Cross Timbers and Prairies vegetational area. As is typical for plants adapted to harsh habitats, sand lovegrass is actually a delicate species. It can thrive in severe environments, but is very susceptible to abnormal stress such as improper defoliation (overuse or even heavy use during early growth). Erath County, Texas. October. Deep Sand range site (sand rough).

44. Flowering shoots of sand lovegrass- The large, showy inflorescence of a climax understorey species on sites of deeper sands such as sand rough. Sand lovegrass grows most abundantly in well-lite natural openings in the oak scrub. It is a satisfactory sand-binding species but is quickly grazed out under excessive stocking rates. Sand lovegrass is an "ice cream species" on range habitats like this sand rough (Deep Sand range site). Erath County, Texas. October.

45. Grapes on perimeter- Mustang grape (Vitis mustangensis) growing on deep sand on outer edge of a sandrough community. This Vitis species is adapted to a wide array of habitats. This particular specimen was in full-bloom. Erath County, Texas. April

46. Blooming on the rough (sandrough that is)- Photograph of mustang grape showing arrangement of inflorescences and leaves along shoots. Deep sand has high infiltration capacity so that remarkable quantities of soil moisture are often available on what otherwise would appear to be a hard-scramble habitat. Erath County, Texas. April, full-bloom phenological stage.

47. Details of mustang grape- Leaves and flower clusters of mustang grape growing on sandrough scrub range. Erath County, Texas. April.

48. Rough-leaf on a sandrough- Inflorescences and leaves of rough-leaf dogwood (Cornus drummondii) growing on outside edge of a sandrough range. The deep sand of this range site has high water infiltration capacity so that a lot of soil moisture is available to plants, at least for short periods of time. This versatile shrub was taking full advantage of recent spring rains. Erath County, Texas. April, full-bloom phenological stage.

49. Roughleaf dogwood blooms- Two views of flower clusters of rough-leaf dogwood thriving on a sandrough range shortly after heavy rains, almost all water of which quickly went into the soil profile of this otherwise tough country. Erath County, Texas. April.

Live Oak (Quercus virginiana var. fusiformis = Q. fusiformis) Scrub

50. Ridge and Swale Live Oak Scrub, Shell Ridge Live Oak Scrub, or Running Live Oak Thicket- All these  explicit titles (and some more) are used, and are appropriate, for a scrub live oak range cover type on deep sands along the coast in the general Texas Coastal Prairies and Marshes Vegetation (= Land Resource) Area. This live oak scrub is what Texans call “running live oak”. It is the shrub form of what is generally regarded as southern live oak (Quercus virginiana) which spreads vegetatively by rhizomes (hence the adjective “running”). The taxonomy of running live oak has not been definitively established, and perhaps cannot be. Not only have numerous plant taxonomists arrived at varying conclusions including, as might be guessed, numerous scientific names at different taxonomic levels, but the oaks both integrade and hybridize. Running live oak has been interpreted as Quercus virginiana var. fusiformis (= Q. fusiformis), Q. virginiana var. macrophylla, Q. oleoides var. quaterna, and Q. virginina var. minima (=Q. minima). As if that is not confusing enough there are at least the following recognized hybrids: Q. minima X Q. virginiana and Q. minima X Q. stellata (post oak), and Q. virginiana X Q. stellata (Correll and Johnston, 1979, ps. 483-484).

While the running scrub live oak is the sole dominant species and the one that forms the general physigonomy of this cover type it is a species-rich thicket. The lianas of mustang grape (Vitis  mustangensis), peppervine (Ampelopsis arborea, another member of Vitaceae), and Alamo vine (Ipomoea sinuata, a woody morning-glory), in that order, grow over the live oak canopy creating the appearance of a camp meeting brush arbor. The usually shaded understory is dominated by yaupon (Ilex vomitoria) and some tanglewood  or panalero (Forestiera angustifolia) along with the stems of the lianas, with scattered grassland forbs like Turks cap (Malvaviscus drummondii), all entangled with cat green-briar or cat-brier (Smilax bona-nox) plus the three above dominant woody vines. At the outer edge and occasional openings in the live oak there  are small trees of laurel oak (Quercus hemisphaerica), Texas persimmon (Diospyros texana), netleaf hackberry (Celtis reticulata), and Mexican buckeye (Ungnadia speciosa) plus a lower layer of tanglewood, lime prickly ash or Hercules club, and young plants of these species.

Aransas National Wildlife Refuge, Refugio County, Texas. October. No FRES Number or Kuchler Unit. Live Oak Thicket variant of SRM 719 (Mesquite-Live Oak-Seacoast Bluestem). Variant of Scrub Oak Series in Southeastern Maritime Scrub biotic community of Brown et al. (1998). Western Gulf Coastal Plains- Mid-Coast Barrier Islands and Coastal Marshes Ecoregion, 34h (Griffith et al., 2004).

The general Shell Ridge Community consist of three distinct communities distributed according to the ridges of the ridge and swale relief: 1) inner ridge, 2) middle ridge, and 3) outer ridge. The outer ridge is the swale-and-ridge gulf grassland included with the Grassland slides above and the middle ridge is a chaparral form not included in this publication. There are gradients in soil water, soil compaction, soil salinity, wind exposure, and surface insolation from the oldest (inner) ridge to youngest (outer) ridge (McAlister, 1988).

51. Detail of the exterior of the Inner Shell Ridge Running Live Oak Scrub- The dominance of mustang grape with pepper vine and Alamo vine as associates in the canopy of scrub southern live oak is obvious. The soil of this range cover type is interesting because it is “an old (about 3,000 years) well-weathered, highly compacted, oystershell base which suffers no washover except from extreme storm tides”  (McAlister, 1988). Aransas National Wildlife Refuge, Refugio County, Texas. October.No FRES Number or Kuchler Unit. Live Oak Thicket variant of SRM 719 (Mesquite-Live Oak-Seacoast Bluestem). Variant of Scrub Oak Series in Southeastern Maritime Scrub biotic community of Brown et al. (1998). Western Gulf Coastal Plains- Mid-Coast Barrier Islands and Coastal Marshes Ecoregion, 34h (Griffith et al., 2004).

52. Interior of the Inner Shell Ridge Running Live Oak Scrub- This is the understory of the running live oak thicket of the two preceding slides. Trunks of live oak, Mexican buckeye, and Texas persimmon can be seen here. Netleaf hackberry is in far background. Lianas include the larger stems of mustang grape and cat green-bria as most common followed by Alamo vine and peppervine. Tanglewood is more common than yaupon in this view. This is deep inside the thicket so species like turk’s cap and lime prickly ash are absent. Grass is absent from the shell ridge live oak thickets.

“The live oak thickets are incredibly dense (up to 50 sturdy stems per square foot, for acres and acres), waist-to-head-high stands of scrubby oak shoots that arise from a ramifying mass of pernicious rhizomes” (McAlister and McAlister, 1987, p. 55).

Ecological status of this vegetation is not known nor is there concensus on its position on the sere for this given range site. The range site was not described by Soil Conservation Service Soil Surveys (actually it was not  recognized as a  range site by the SCS). The traditional interpretation of much, probably most, of scrub vegetation in humid, subhumid, and semiarid regions has been that of a woody invasion induced by human abuse through overgrazing, underburning, cultivation, mining activity, etc. Arid regions are a clear exception as deserts are, by definition, shrublands. Exceptions under semiaridity include California and Arizona chaparral, shinnery oak, Gambel oak, and bigleaf maple seen in these Shrubland slides. The sandrough range type of the subhumid zone of central Texas was defined as postclimax oak scrub persisting on deep sand in a regional climax of tallgrass prairie and tallgrass prairie oak-hickory savanna (the Cross Timbers). The old, weathered, saline, droughty yet deep oystershell-sandy soil of the Inner Ridge suggested to this author that some of this vegetation was likely an edaphic climax scrub. Undoubtedly there was encroachment of this cover type into the regional or climatic climax grassland, a woody invasion and typical Texas brush problem. Undoubtedly this is the situation for most of the running live oak in the Coastal Prairies and Marshes Region. It also seemed obvious however that there had to be a “nucleus” or source of propagules for what is a very unique and diverse plant community. These scrub oak thickets are not just conglomerations of woody plant species which typically occur as scattered individuals as a savanna in a sea of grass. It is hard to imagine the lianas existing as infrequent plants in a grassland but which “thickened up” in absence of prairie fires. Throughout most of its range yaupon appears as an understory species. Turk’s cap is one herbaceous species existing on the climax grassland, but it is present mostly along the outer edges of live oak thickets. It appeared most likely that in the virgin vegetation the Inner Ridge supported running live oak thickets as edaphic climax scrub as “islands of shrubs in a sea of grass”, a vegetation mosaic that included seral stages in areas recovering from local disturbance and maintained by climate, soil features, and large-scale disturbances like drought, fire, hurricanes, migratory game, etc. The Inner Ridge Live Oak Thicket is likely a postclimax range community but as the potential natural vegetation running live oak thickets would be quite restricted in scale and area. Expansion of thickets beyond the Inner Ridge would be interpreted as retrogression of range vegetation due to human abuse.   Most of this running oak thicket range type is the ultimate example of range deterioration. It is a woody disclimax which has achieved a “stranglehold” on what were once a pristine sea of grass and that now cannot now be controlled without harming other species of features of the prairie community (McAlister and McAliste, 1987, ps. 53-54). It serves as a dire warning: “Only you can prevent range abuse”. Small portions that are most likely the potential natural vegetation (an edaphic climax) serve as an example of how interesting and interrelated range plant communities are.

53. One thing we can all agree on: would be one a helluva place to chase a cow. Inside the Inner Shell Ridge Running Libve Oak Scrub Type. Aransas National Wildlife, Refugio County, Texas, October. No FRES Number or Kuchler Unit. Live Oak Thicket variant  SRM 719 (Mesquite-Live Oak-Seacoast Bluestem). Variant of Scrub Oak Series in Southeastern Maritime Scrub biotic community of Brown et al. (1998). Western Gulf Coastal Plains- Mid-Coast Barrier Islands and Coastal Marshes, 34h (Griffith et al., 2004).

Willow (Salix spp.) Scrub

54. Riparian Willow Scrub Type- Along watercourses— especially mountain streams, creeks, and small rivers— from the Rocky Mountains to the Sierra Nevada-Cascade Ranges and even Pacific Slope drainages there are diverse range communities dominated by shrubs and small trees of the Salicaceae, typically willow (Salix spp.) and cottonwood or aspen (Populus spp.). Some of these riparian plant communities may be disclimaxes induced through disturbances such as overuse/overgrazing by livestock or wildlife like beaver (Castor canadensis) which concentrate along the watercourses. Other disturbances include logging and flooding (especially upstream) due to activities like road-building or hydraulic mining. Many of these salicaceous communities, however, are natural (= climax) vegetation. Willow scrub (of various forms) appears to be a riparian climax.

Strawberry River, Unita National Forest, Wasatch County, Utah. Vernal aspect, June. SRM 422 (Riparian) as a Great Basin Cover Type is general and quite variable but appears to describe the riparian willow shrubland range type. Also SRM 921 (Willow) Rangeland Cover Type of Alaska is the boreal equivalent of the riparian willow of Great Basin and western mountain streams. Grayleaf willow (Salix glauca) is one of the dominant low willows while Bebb willow (S. bebbiana) is a dominant tall willow. Both of these species occur in the Intermountain Region and along Utah streams (Welsh et al., 1993, ps. 628, 630). Willow Series in Rocky Mountain Alpine and Subalpine Swamp and Riparian Scrub biotic community or perhaps in Plains and Great Basin Riparian Scrub biotic community of Brown et al. (1998).Colorado Plateau- Semiarid Benchlands and Canyons Ecoregion, 20c (Woods et al., 2001).

55. The willows are one of those taxonomic nightmares for all but veteran taxonomists. Welsh et al. (1993) described over two dozen species of Salix found in Utah. What is more Salix species hybridize readily. Viewers can have their choices as to species. This is a willow thicket pure and simple. Strawberry River, Unita National Forest, Wasatch County, Utah. Vernal aspect, June. All riparian sites are prone to damage by overgrazing/overbrowsing— especially by larger animals which tend to “hang in on water” —because of the availability of water and shade, fairly level terrain, congregation of fellow animals, etc. While the riparian habitat is ideal for high yields of browse and members of Salicaceae are well-adapted to it and to defoliation they can be overbrowsed (Despain, 1990, p. 82, 94, 98-101). This includes by wildlife. Despain (1990) discussed the impact of wildlife overbrowsing on willow and quaking aspen in Yellowstone National Park. Even his optimistic interpretation could not ignore the severe loss of wildlife browse in parts of  Yellowstone which should be a model of pristine environments, including riparian vegetation. Overuse of riparian vegetation remains a problem in National Parks where native predators are rare or absent. McName (1997, ps. 170-171) wondered if willow and quaking aspen would rebound if the wolf was reintroduced into Yellowstone National Park. Willows have the zig-zag or sympodial growth pattern in which the upper potion fo the leader is routinely aborted (Sosebee, 1977, p. 277). Proper degree of use is very critical in shrubs like willows because they have aboveground perenniating parts. It was discussed under forest grazing that most woody plants are phanerophytes which due to location of meristems are the growth or life form most vulnerable to defoliation. For utilization evaluation in shrubs see Interagency Technical Reference (1996). Not only can the riparian vegetation be damaged by long-term overutilization but prolonged concentration of animals can lead to physical damage to the geomorphological aspects of streams such as bank-caving. Chemical harm may occur by excessive deposites of dung and urine and high levels of coloform bacteria (ie. pollution). These combined effects can readily lead to degradation of the riparian range site, including damage to fish habitat (eg. loss of shaded banks needed for proper temperatures for eggs and fye). Under multiple-use management “writing-off” riparian ecosystems as sacrifice sites is no longer an acceptable practice. Some would argue that it was never proper management noting that turning creeks as sources of clean, fresh stock water into ditches of polluted, stagnant water is poor animal husbandry and an unacceptable practice from the standpoint of herd health. A comparison of damage to willows (and stream bank) by animal concentration versus reduction or elimination of animal concentration with resultant willow recovery was presented below in this willow series. Fortunately, this problem was recognized— belatedly but finally —and many conscientious stock-growers worked with conservationists like sportsmen and natural resource agencies to achieve proper animal distribution on ranges blessed with watercourses. Management of riparian range sites is extremely difficult from both the  physical/biological and economic standpoints because fencing streams is usually not cost-effective. Cross-fencing pastures having streams so as to reduce concentration of  livestock or duration of livestock concentration is more economically efficient but can also be expensive. Fencing may be used with specialized forms of grazing management to better manage distribution of animals and season of use. Changing season of use or changing kind or class of livestock is sometimes possible by better incorporating management of grazing units into total ranch management. Smaller ruminant species like sheep are more likely to rustle farther from water than larger ruminants like cattle. There are even breed differences within a species.  One of the most cost-effective (and romantic) ways to manage ranges containing delicate riparian sites is the time-tested use of range riders or sheep herders to herd livestock thereby achieving proper distribution of animals on range. This noble occupation traces its recorded lineage back through Abraham, Moses, David, the Good Shepherd, and Charlie Russells (and our own) Trail Boss. The most enduring of all American folk heroes is the cowboy. For the scientific approach to the art of herding livestock Moving ‘Em by Smith (1998) is highly recommended.

“My heroes have always been cowboys.”

—Willie Nelson

Now watch the ole range prof get in the Four Cardinal Principles of Range Management:

Proper Degree of Use Proper Distribution of Use Proper Season of Use  Proper Kind and Class of Range Animal.

The literature on range management on riparian ecosystems and riparian vegetation is seemingly infinite attesting to its importance. It is the one area where even the most die-hard anti-environmentalists agree on the need for inproved range management. Great strides have been made, including by the livestock industries. Continued effort in this as in all areas of management will be necessary. The following are recommended as a start in the literature of riparian range management: Myers (1989), Smith and Prichard (1992), Leonard et al. (1997), and Winward (2000). The range industry continues to carry many “success stories” on riparian range management.

56.  Willow leaders- Twigs with pistillate catkins, leaves, bark, and buds of a tall Salix species. Salix species are dioecious. These are leaders of a female plant. The zig-zag pattern of twig growth in willow is obvious here. See the two aborted (dead and brown) leaders. Strawberry River, Unita National Forest, Wasatch County, Utah.

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57. Riparian Willow Scrub- This example of a willow-dominated range community grew along a section of the Donner-Blitzen River in a transition of High Lava Plains and Basin and Range provinces (generally known as the "Oregon High Desert"). Dominant species was narrowleaf or coyote willow (Salix exigua) though there were other Salix species as well that were associates. Another local associate was cluster or peafruit rose (Rosa pisocarpus). Except at edges of willow growth, there was little if any understorey the dense shrub canopy precluding development of such layer(s). Malheur National Wildlife Refuge, Harney County, Oregon. J:une. No FRES ecosystem or Kuchler unit at the lengthy but "strip" (narrow-width) scale of this riparian vegetation. SRM 422 (Riparian) as described in previous captions. Coyote willow association of Kagan et al. (2004). Northern Basin and Range- High Desert Wetlands, 80e (Thorson et al., 2003)

58. Narrowleaf willow (Salix exigua)- Pistillate inflorescences and identifying petiole-like leaf apices of a dominant ripraian species in the Oregon or Harney High Desert. Malheur National Wildlife Refuge, Harney County, Oegon. June.

59. Wetland willows- Most willow species (Salix spp.) are intimately associated with free (surface) water. Willows are commonly found growing along streams (of sundry sizes and water temperatures), and are thought of in such context by most viewers of vegetation. Throughout much of the "Far West" (say, Rocky Mountains to Pacific Ocean) and, in particular along mountain streams, development of willow-dominated plant communities extends beyond the riparian zone into bottomlands adjacent to streams where later flow of water creates a subirrigated environment. Willow communities often expand to such degree as to ultimately occupy the entire subirrigated site (unless their expansion is checked by human management). With a large number of multiple shoots per individual shrub (genetic individual or genet) willows often form a community closed to other species except in the limited interspaces among individual willows. Successional status of such wetland scrub vegetation continues to be discussed by scientists and laymen alike, but has not been resolved (at least not to this author's knowledge or satisfaction). Human management to willow communities varies with most ranchmen favoring some degree of control of woody species that they regard as pests (ie. brush or noxious woody plants) while sportsmen (eg. fishermen) and landowners wishing to "leave it natural" opt for willow maintenance or even increase. This photograph illustrated the situation just descriped. Control of willows would allow development of a wet (subirrigated) meadow of sedges and grasses (with or without clumps of willows depending on degree of control). The "mixture" of willow and grass-grasslike vegetation shown here was the result of "leave it alone" or "let Nature take her course" management. This willow stand/meadow range had been grazed by beef cattle and, presumedly, by mule deer. Result was an apparent stable plant community with soil protected against erosion except immediately along stream bank (see slides below). Situations (vegetation, human use, wildlife habitat, land stability) like the one viewed here are common in many areas throughout the West and on both public and private land. This photograph showed physiognomy and architecture of a wetland willow scrub range, including herbaceous interspaces of sedges and mesic or hydric grasses. Along Silvies River, Grant County, Oregon. June. No FRES or Kuchler units for willow scrub (vegetation not mapped to such small-scale units. SRM 422 (Riparian). Blue Mountains- Melange 11d (Thorson et al., 2003).

60. "Inside a willer thicket"- Interior of the willow scrub community of the preceding slide. Such range vegetation provides cover for both some species of wildlife and reclusive cows. The protection afforded by the dense willow cover is often ideal for calving, fawning, etc. It is, however, not the sort of protection necessary for calving heifers or desirable when gathering cattle. Such thickets are literally impenetrable even to skilled buckaroos but such scrub does make the case for good cow dogs. "'Sic her, Hank". Along Silvies River, Grant County, Oregon. June. No FRES or Kuchler units for willow thickets. SRM 422 (Riparian). Blue Mountains- Melange 11d (Thorson et al., 2003).

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61. Damage (disturbance) to vegetation and stream bank by animal concentration- Two views showing elimination of willows and all other plants along with soil disturbance due to congregation of cattle along a streatch of Silvies River in the Blue Mountains province of central Oregon. Mule deer also range freely across this land, but as shown below damage to vegetation and soil surface and stream bank was limited to low river banks readily accessible to cattle. Streatches of Silvies River on either side of this cattle range that had mule deer but not cattle grazing showed no such disturbance. Deer tracks were not found among cow track in the mud of the river bank. Silvies River, Grant County, Oregon. June. SRM 422 (Riparian). Blue Mountains- Melange 11d (Thorson et al., 2003)

62. Vegetation and stream bank not damaged by cattle- This streatch of Silvies River was immediately upstream (about two cow-lengths) from that shown in the immediately preceding slide. Defoliation of herbaceous plants was obvious on the top of the river bank but not down on the steeper sides (Steepness apparently deterred cattle use of forage up to water's edge in contrast to the situation presented in the two previous slides.) Cattle grazed herbaceous plants right up to large willows and did not proceed farther up river or move into the dense willow colony. Impact of cattle on this riparian range ecosystem would require careful analysis. Damage to river bank and potential for erosion and modification of stream channel were undisputable. Removal of vegetation and soil trampling in the area that resembled a hog wallow eliminated shading of water (compare this slide to the two immediately above). This certainly could increase water temperature in that streatch of river with potential detrimental impacts of cold-water fish like trout. Change in water temperature would also be partly a function of rate of water movement as well as initial water temperature and quantity of water exposed to radiation. Analysis of cattle influence on this range ecosystem, including aquatic habitat as well as soil and vegetation, might (or might not) indicate that the sacrifice area seen here was of such size as to have (or not have) an overall detrimental effect. Certainly cattle impact along portions or sections of the stream looked "real bad" and degree of use of herbaceous species beyond the river seemed excessive. It is possible, however, that adequate streatches of the river were protected (even in the cow pasture due to natural barriers of vegetation and stream morphology) with net result of little or no detrimal impact on the range or aquatic environment. This case was beyond any doubt a "black eye" for the beef cattle industry that has made remarkable progress in proper management of riparian range sites. This cattle-owner will not be receiving the National Cattlemen's Beef Association Environmental Stewardship Award any time soon! Public relations aside (though just as important), the exact or actual influence of such disturbance on the range and such range resources as the river require objective and detailed analysis. Silvies River, Grant County, Oregon. June.

63. Recovery of vegetation- This portion of Silvies River was immediately beyond that streatch that was a "stomp lot". This section can be seen at the end of the disturbed streatch shown in the first of two slides two captions immediately above. Cow hoof-induced soil at water's edge was visible in this photograph. Yet young willow shoots had risen along the river bank and for considerable distance away from the actual riparian zone into the subirrigated bottomland. One critical aspect of riparian grazing (proper management of riparian and adjoining range sites) is ecosystem resilience and rate of recovery. Fortunately, the "ideal" habitat of most riparian areas and sites ("ideal" for plant growth in this meaning) and potential for soil stability even in these flood plains and terraces is such that recovery from damage or disturbance (natural or human-induced) is among the fastest for any ecosystem. This fact partially explains the many delightful "success stories" of restoration projects on riparian ranges and associated streams. Given this relatively high likelihood of success, numerous "stake-holders" like stockmen, fishermen, backpackers, agency folks,.and even Boy Scouts have "rallied to the cause" and aided restoration of riparian and related natural resources. Recovery of willows along this stream immediately adjacent to disturbed riparian sections attested to the high potential rate of recovery and good chances for restoration of damaged riparian range. Further conservation of such natural resources depends on continued proper grazing management. Silvies River, Grant County, Oregon. June.

64. Black willow (Salix nigra) swamp- The black willows in this stand can be interpreted as either small trees or, given the multi-stemmed growth habit, large shrubs. They are in the backwater riparian zone of the West Branch of the Trinity River in the general Cross Timbers and Prairies Region of northcentral Texas. As noted above, the successional state or seral or climax is unknown and there is neither FRES nor Kuchler designation for willow, but this could be an example of a seral stage of the sycamore-pecan-American elm type as suggested by Garrison et al. (1977, ps. 15-16 ) which puts it in climax FRES No. 17 (Elm-Ash-Cottonwood Ecosystem). Such a state would place this community as a seral stage of SAF 94 (Sycamore-Sweetgum-American elm), but SAF 95 (Black Willow) nails it perfectly at this stage. Cottonwood-Willow Series in Southeastern Swamp and Riparian Forest biotic community of Brown et al. (1998). The low-growing twigs are within easy reach of browsing white-tail deer and sign of beaver feeding on willow bark was common. Forth Worth Nature Refuge, Tarrant County, Texas. October. Cross Timbers- Grand Prairie Ecoregion, 29d (Griffith et al., 2004).

65. Black willow (Salix nigra)- Whole shoot of one black willow plant growing on pond dam in Grand Prairie of northcentral Texas. Typical habit of this multi-stemed large shrub or small tree. All members of the Salicaceae (willow or poplar family) are dioecious (separate male and female plants). This plant was a male. Staminate catkins of this specific plant were presented below. Erath County, Texas. April.

66. Some shoots of black willow- Several young trees or shrubs of black willow growing in the floodplain of the Wichita River. Wichita County, Texas. October.

67. Black willow flower- Staminate catkins of the black willow growing on pond dam in Grand Prairie in northcentral Texas (same plant) that was presented above. Willow species are dioecious (having separate male and female flowers on different plants; individual plants are either male or female). Erath County, Texas. April.

Rio Grande (Rio Bravo) Vegetation

Riparian willow scrub and mesquite bosque vegetation develops and exists as adjacent zones of climax range plant communities along watercourses and their drainages in southwestern North America. Much of this range vegetation pattern occurs in regions characterized by aridity and semiaridity. Both of these vegetation zones constitute range cover types. The willow cover type was considered immediately above and continued here in conjuction with the mesquite bosque type because these two communities occur together as integral parts of a common landscape. Mesquite bosque occurs as a band or zone of potential natural vegetation between the vegetational mosaic of Chihuhuan Desert-semidesert grassland and riparian willow scrub (along with Phragamites communis grassland which was covered under the Miscellaneous Grasslands chapter). Willow shrubland and mesquite bosque were organized and described as a subchapter because of the close spatial association and ecological interactions of these two ecosystems that were described here as range cover types.

Directional Note: In an effort to avoid confusion and frustration of readers it was again emphasized that reedbed or reedbank grassland made up of common reed (Phragmites commnis= P. australis) which grew end-to-end with willow scrub along banks of the Rio Grande was interpreted as a range cover type of grassland and as such was treated under the Grasslands biome as the Miscellaneous Grasslands chapter.

Willow (Salix spp.)

68. Route of the river- Land forms and vegetation defined by two rivers:. the Big Bend stretch of Rio Grande in the Trans-Pecos drainage of the Basin and Range province provides an environment for riverine vegetation in the midst of the Chihuhuan Desert. In the far background the Rio Grande emerges from Santa Elena Canyon. This is a chasm with sheer walls up to 1500 feet deep cut through the limestone of Sierra Ponce (the Chihuhua side in the left two-thirds of the background) and Mesa de Anguila (the Texas side in the right one-third background) by sand-laden, moving water over geologic time. Sierra Ponce- Mesa de Anguila are a mesa, "an uplifted block of Lower Cretaceous limestone", that is the remainder of a former and much higher mesa from which the softer Upper Cretaceous limestones and shales were eroded (Maxwell, 1968, ps. 87-89). Even short of its previous glory the mesa is a backdrop land form to a once-mightier river that now relies on another river, the Rio Conco, for most of its water.Even with most Rio Grande water dammed and diverted for human agricultural and municipal uses, there is adequate aquatic environment for well-defined range cover types. Immediately along the river banks (or back a short distance where there are recently formed sand bars) there is a zone of riparian vegetation made of two end-to-end disparate plant communities or, perhaps more descriptively, stands: 1) willow and 2) reed. The woody vegetation (a willow shrubland) and the herbaceous vegetation (a grassland of common reed [Phragmites communis]) are each spatially short and narrow "strips" of distinct plant communities which obviously interact yet are physically segregated. There are of course other plant species in the willow and reed communities but the two species so dominate their respective vegetation that most other species seem of miniscule importnce, at least from standpoint of range cover types. Adjacent to riparian vegetation on the river flood plain and covering a much broader breath of rangeland is vegetation known as bosque or bosques (mostly an Anglo-adopted Spanish word). Bosque vegetation is dominated by mesquite and other woody plants, most of which are of shrub rather than tree form and dimension. Willows are also usually shrubs or, at most, small trees. In restricted locations along short stretches of the Rio Grande riparian vegetation consist of large cottonwood trees, often with willows as a lower woody layer, that form small gallery forests. These gallery forests were treated separately under Miscellaneous Forest Types and Southern and Central Forests (Woodlands and Forests). Gallery forests were not discernable in these landscape-scale photographs. Technical Note: The term riparian may have somewhat different meanings or connotations as used Hydrology, Aquatic and Riparian Ecology, Range Management, or Forestry not to mention legal usages in the extremely specialized area of water law and policy. The Glossary of Hydrology (Wilson and Moore, 1998) defined riparian thusly: "Pertaining to or situated on the bank of a body of water, esp. of a watercourse such as a river; e.g. 'riparian land' situated along or abutting upon a stream bank..." (listed as synonyms were riparial and riparious). A Glossary of Terms Used in Range Management (Jacoby, 1989), an official publication of the Society for Range Management, defined riparian as: "Referring to or relating to areas adjacent to water or influencecd by free water associated with streams or rivers on geologic surfaces occupying the lowest position on a waatershed". Jacoby (1989) defined riparian zone: "The banks and adjaacent areas of water bodies, water courses, seeps and springs whose waters provide soil moisture sufficiently in excess of that otherwise available locally so as to provide a more moist habitat that that of contiguous flood plains and uplands". Clearly, hydrophytic or streamside (= riparian) vegetation such as that dominated by willows and reeds on the edge of the Rio Grande constitutes plant communities not only different from other vegetation, but growing on a different environment from that on and of the flood plain. Alternating patches or strips of willow and reed vegetation were clearly visible in both of these photographs. Also readily discernable was the more extensive (and drier-soil) area of mesquite bosque that had developed adjacent to riparian zone vegetation. Land in the immediate foreground was on an upland overlooking the Rio Grande and Sierra Ponce-Mesa de Anguila that provided a vista of riparian and flood plain vegetation. Vegetation on the upland foreground (vista point) was Chihuhuan Desert dominated by the climax species, creosotebush (Larrea tridentata) and tasajillo or pencil cholla (Opuntia leptocaulis). Quite a study of and contrast in range vegetation. Big Bend National Park, Brewster County, Texas. June.

69. River bank willows- Along this reach of the Rio Grande willows lined both river banks and formed plant communities consisting almost exclusively of vrious species of willow. Sandbar willow (Salix interior= S. exigua) was by far the most common species, but black willow (S. nigra) and yew-leaf willow (S. taxifolia) were present, even relatively abundant, locally. The conspicuous green grass in the understorey (right foreground) was naturalized common bermudagrass (Cynodon dactylodon). Common bermuda is one of the most widely distributed naturalized grass species on Earth. Students take note of the multi-trunk form --usually the key feature distinguishing shrubs from trees-- of willows. Also take note of the readily available browse produced by willows. The escarpment of Sierra Ponce mesa in Chihuhua formed the background. Big Bend National Park, Brewster County, Texas. June. No appropriate FRES, Kuchler, or SRM for units of vegetation this small and/or in southwestern North America. SAF 235 (Cottonwood-Willow). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).

70. Willows at water's edge- Stand of coyote or basket willow in the riparian zone of the Rio Grande. Willows and a few other species like naturalized common bermudagrass formed riparian plant communities lining both banks of the Rio Grande. River banks comprised primarily of flooded sand were raised at considerable heights above "normal" or regular river height by deposition during periods of high water (flooding). Willows quickly established on the sand alluvium and stabilized banks thereby minimizing soil erosion and lowered water quality. Willow species reproduce by both asexual (= vegetative) and sexual means. Vegetative propagation consist of producing new shoots ("baby trees") from creeping rootstocks (rhizomes) of mature willows. Results of this process of producing clones or modules of existing adult trees was obvious in foreground of this photograph. "Root suckers", as these asexual secondary shoots are frequently called, also provide high-quality browse for species of range animals. Even grass-preferring grazers like cattle and elk will browse and consume copious quantities of such range feed. Range managers must carefully watch and manage this utilization of browse to prevent overbrowsing and instead insure perpetuation of willows (or cottonwoods to which the preceding applies equally). It was clear from this slide that vegetative reproduction is essential in Salix species, and that this in turn is essential to prevent accelerated soil erosion and sedimentation (deposition of eroded soil called sediment). Lower portion of the limestone escarpment, Sierra Ponce, in Chihuhua provided the background. Big Bend National Park, Brewster, County, Texas. June. No appropriate FRES, Kuchler, of SRM unit. SAF 235 (Cottonwood-Willow). Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).

71. Sandbar or coyote or basket willow (Salix exigua= S. iinterior)- Sandbar willow is the major Salix species of willow communities in the riparain zone of the Rio Grande.This is also the dominant species of such riparian range vegetation. Stands of coyote willow like those shown in the two immediately preceding photographs consittute a consociation. Basket or interior willow is most commonly a shrub not a tree. The multi-stemed habit (feature of numerous shoots or trunks) is usually the main distinguishing feature that differentiates shrubs from trees. The multi-shoot morphology of willow was quite pronounced in this single specimen. This is one plant, one genetic individual (= a genet), in which each shoot (trunk with limbs and branches) is a clone (= ramet). Sandbar willow also reproduces sexually (stay tuned). Big Bend National Park, Brewster County, Texas.

72. Willows waving from the shore- In the riparian zone branches and leaves of sandbar or interior willow that formed narrow yet dense stands on sand banks of the Rio Grande. This is the most common and most often the dominant Salix species in this area. Twig tips, buds, leaves, and bark of willows is extremely valuable browse for many kinds of range animal from domestic and native ruminants to beaver (Castor canadensis). Willows are of more immediate value in stabliizing the erosion-prone channels and banks of Rio Bravo. Some such erosion is natural (= geologic) erosion which of course is essential to landscape and ecosystem function. It was action of sand-laden water moving over course of river and time that carved magnificant canyons like Santa Elena through the Upper Cretaceous limestone of the Sierra Ponce-Mesa de Anguila escarpment visible in the background. Big Bend National Park, Brewster County, Texas. June..

73. Catkin of coyote or sandbar willow, and "Its a girl"- The inflorescence type in Salicaceae, the willow or cottonwood family, is the catkin or ament defined by Smith (1977) as "an inflorescence characterized by typically unisexual, apetalous, bracteate flowers in a pendant cluster". Salix species are dioecious, but most like S. interior shown here are monoecious. It was shown in some of the preceding photographs that most reproduction in sandbar willow is vegetative (asexual). The plant shown here, however, was apparently enjoying the renewable pleasure of sex.This catkin was female. Big Bend National Park, Brewster County, Texas. June.

Mesquite Bosque

Honey mesquite (Prosopis glandulosa) forms one climax range plant community that can be recognized--and probably incontrovertably--as a range cover type. There may be more than one, but there is one kind of potential natural vegetation that even the most ardent, kill-it-any-way-you-can, hard-core, the-best-mesquite-is-a-dead-one mesquite haters (eg. this author) recognize as something besides a noxious woody invasion. That range vegetation is what Kuchler (1964, p. 27; in Garrison et al., 1977 as unit K-23 under Desert Shrub Shrubland Ecosystems) entitled and described as Mesquite Bosques. Kuchler (1964, p. 27) limited occurrence of Mesquite Bosques to southern Arizona (in the United States) and Kuchler did not include this unit in his map of potential natural vegetation in Garrison et al.(1977), but rangemen throughout the greater Southwest realize that Mesquite Bosques extends from Texas across to southern California and far down into the Mexican states (eg. Chihuhua, Sonora). Mesquite was recognized by Kuchler (1964) and Garrison et al. (1977) as a dominant species in other climax units of potential natural vegetation including Mesquite Savanna and Mesquite-Acacia Savanna (Kuchler, 1964, ps. and units 60 and 61), but Mesquite Bosques is a closed canopy shrubland or even low-stature woodland not savanna. Mesquite Bosques has limited herbaceous understorey in contrast to the dominant and defining herbaceous layer(s) as in savanna range cover types. This distinction corresponded roughly to that by the Society for Range Management (Shiflet, 1994) in which type-describer Bill Dahl distinguished SRM 727 (Mesquite-Buffalograss), SRM 728 (Mesquite-Granjeno-Acacia), and SRM 729 (Mesquite). Likewise the Society of American Foresters (Eyre, 1980) recognized SAF 68 (Mesquite). To some degree similarities among these units of vegetation were greater in title than in detailed description, but even in that regard there was a consistent understanding among various vegetation scientists that mesquite does develop into dense natural plant communities along stream corridors and/or adjacent habitats. "On some bottomland sites, however, honey mesquite grows to tree size and stands assume characteristics of a forest" (Eyre, 1980, p. 71). Bosque is an interesting term. Bosque is more-or-less Spanish (it might be somewhat less so than commonly assumed as explained shortly) that was "adopted" by and has persisted in a predominately Anglo culture. In fact, bosque is one of the iconoclastic Spanish nouns (like mesa, coyote, and rodeo) that, except for slightly different pronounction, became incorporated into popular culture and that conjures up an agreed-upon image. Bosque is Spanish for "wooded thicket", but the term is very similar to (and consistent with) bosquet, the French word for "thicket" that in turn was derived from busk meaning "forest". In states like Texas where there is a rich heritage and history of French as well as Spanish occupation (ie. a legacy of La Salle as well as Columbus, Coronado, and Cortez) it is understandable that an Anglicized "bosque" would persist. An example is the Bosque River in central Texas. As "bosque" is used today-- in both popular as well as professional-scientific usage-- the term applies to (and brings to minds of most users an image of) woody vegetation growing on flood plains or generally low-lying environments with mesic or, infrequently, hydric soils and dominated by mesquite, salt cedar (Tamarisk spp.), willow, cottonwood, seep willow or willow baccharis (Baccharis salicifolia) or, less commonly, other woody angiosperms like ash or oak. With continued ecosystem-threatening invasion of saltcedar (esp. T. chinensis= T. ramosissima), and cooperative programs attempting eradiction of this non-native species, "bosque" is often first thought of as thickets (or forests) of saltcedar or saltcedar and mesquite growing along streams including major rivers. For example, Brown et al. (1998, p. 44) listed Saltcedar Disclimax Series and Seepwillow Series under Southwestern Interior Swamp and Riparian Scrub biotic community. Even before (and hopefully there will be an "after") saltcedar invasion there were various other species of woody plants besides mesquite (as well as herbaceous plants) in bosques. There are even other species of native woody legumes. Honey mesquite was (is), however, so dominant and provided the key physiogonomic element that the designation "mesquite bosque" was "only natural" (no pun intended). Honey mesquite is generally regarded as a facultative phreatophyte, a plant species that can function as a "well plant" (one with some of its roots in the capillary fringe just above the water table) yet one in which this feature is not a requirement as it is in obligate phreatophytes. Woody species that have been regarded as olbigate phretophytes include saltcedar, willows, and some cottonwood species (Barbour et al. 1999, p. 553). Based on field observations, the current author felt that the preceding categorization seemed far too general. Saltcedar is commonly found growing on habitats where it could not possibly "tap" the capillary fringe or where its roots are far from subirrigated soils. Without definitive studies it seemed apparent that most plant species on Mesquite Bosques are facultative phreatophytes. In this vein-- and in the organization of the current publication-- it was impertive to distinguish between actual or strictly riparian (= streamside or stream corridor) vegetation and vegetation on flood plains or habitats in close proxomity to water courses. The latter plant communities are not literally riparian or partially aquatic though such communities are often adjacent to (or in very close to) riparian vegetation. Both of these categories or general groups of range vegetation are on wetlands and they are, therefore, wetland range communities. The difference is roughly between more-or-less permanently saturated soil of riparain environments and the sometimes satuirated but usually mesic-more-than-hydric water condition of environments at greater distances from watercourses. This difference could be seen as that between permanently or, at least, seasonally wet or water-covered versus intermittently wet or water-covered. The concept of flood plain is central to this understanding. "Wet" (water-covered) whenever the watercourse is within its banks is riparian; "wet" (water-covered) only when the watercourse is outside its banks (ie. flooding) is flood plain. Riparian (as in riparian zone) was distinguished from flood plain by the Society for Range Management (Jacoby, 1989). This was quoted above in a Technical Note inside the first photograph caption under the Willow portion of Rio Grande Vegetation. This somewhat arbitrary yet obvious distinction is basic to describing and providing examples of range cover types. Mesquite bosques usually or naturally (eg. without drastic disturbance such as engineering activieties on rivers) develop as a zone of vegetation adjacent to the riparian zone, this latter of which usually includes obligate phreatophytes such as numerous species of willow. Willows are a wetland scrub (= one kind of shrubland) . The willow range cover type was treated immediatlely preceding this treatment of the mesquite bosque. There are also herbaceous plant communities that are riparian vegetation and that are composed of obligate phretophytes. One of these that is climax vegetation and a rangeland cover type and that develops as a vegetation zone between streambank and mesquite bosque is the common reed (Phragmites communis) community.This is grassland, a restricted kind or form of the grassland biome. The common reed community was covered under the chapter, Miscellaneous Grasslands (grasslands biome). The example of mesquite bosque treated here was along the Big Bend of the Rio Grande (Rio Bravo). Riparian vegetation of willow and common reed were, except where confined in canyons, bordered by flood plain vegetation, primarily by the mesquite bosque cover type. The photographs were taken either 1) inside Big Bend National Park where there was a saltcedar eradication program underway or 2) along stretches of the Rio Grande where saltcedar was absent or only a minor component of the vegetation. This was consistent with the purpose of showing natural (or naturalized) vegetation as it related to range cover types. Range improvement practices --including essential brush control-- was viewed as another topic. Viewers should scroll back up to the first two photographs presented under Rio Grande willow scrub to see location of the mesquite bosque, especially in regards to riparian range plant communities and upland Chihuhuan Desertscrub. Now view the bosque vegetation. Use the "notch" of Santa Elena canyon in Sierra Ponce-Mesa de Anguila escarpment as your landmark. Next slides please ...

74. Mesquite bosque along Rio Bravo- The panarama of land form and vegetation were captured in these views of the broad flood plain of the Rio Grande where it emerges through Santa Elena Canyon. This river-carved "notch" has walls up to 1500 feet heigh (deep) where over geologic time moving, sand-carrying water cut thorugh the escarpment, the mesa, of Sierra Ponce (in Chihuhua and to left of the canyon)-Mesa de Anguila (in Texas and to right of canyon). As the Rio Bravo spilled out of Santa Elena Canyon it spread sand-bearing water across its flood plain leaving the alluvial sand (and other suspended particles and soil separates) to build up soil across this delta and providing water in a deset or semidesert (arid either way) for range plants. Soil moisture conditions were (are) mesic on the delta or flood plain and not hydric as in the riparian zone. Available soil water content (chresard, the amounf of water available for plant use) is a function of both plant species as well as edaphic (of or pertaining to soil) features. The flood plain phenomenon is a function of many and varied factors, but the three-way interaction of water, soil, and plants is primal. Riparian range plant communities like willow and reed develop in the riparian zone of mostly permanently wet rooting medium (saturated soil; soil water content greater than field capacity). . Flood plain range vegetations develops on soils that are ephemerally or seasonally wet ("water-logged"), but that are below field capacity for prolonged periods of time such that plant stress due to water shortage sometimes to frequently exist. Species of plants that can but do not have to function as phretophytes (facultative phreatophytes) often thrive on such soil and water conditions. In addition sandy soils more readily absorb water (ie. have greater rates of infiltration) so that a greater quantity of overflowing river water (as well as that from precipitation) soaks into the soil for later use by plants. A bosque is frequently the vegetational outcome of such plant environments along flood plains (and zones of soil moisture outward from the hydric riparian zone) on rivers in southwestern North America. Typically, native plant species that dominate bosques are facultative phreatophytes, honey mesquite being numero uno among these. While mesquite was the main beneficiary of such natural irrigation and fertilization other native woody legumes include screwbean or tornillo (Prosopis pubescens), retama (Parkinsonia aculeata), Texas paloverde (Cercidium texanum), blackbrush or chaparro prieto (Acacia rigidula), and huisache (A. farnesiana). All of these species are present along the Rio Grande flood plain at one location or another. Another native shrub common on bosques (though more on the outer, hence drier, parts) is seepwillow or jara (Baccharis salicoflia). Saltcedar, a species introduced (probably by nurseymen and, ironically, by the United States Department of Agriculture) from the Old World (most likely the Mediterranean Region), locally dominates bosques. Control practices have been applied to saltcedar on parts of the Rio Grande (eg. in Big Bend National Park) and along much of the reach of the Pecos. A few plants of saltcedar were discernable by their light pink-colored flower clusters. Herbaceous species are limited in the understorey of bossque vegetation probably as a consequence of shade from shrubs. Interesting enough many of the dominant grasses are annual cool-season Eurasian, mostly weedy, species that can get adequate light at seasons when deciduous dominant shrubs are without leaves. Examples include redor foxtail brome (Bromus rubens), Japanese brome or chess (B. japonicus), and little barley (Hordeum pusillum). Native perennial grasses include inland saltgrass (Distichlis stricta= D. spicata var spicata), tobosagrasa (Hilaria mutica), and fluffgrass (Tridens pulchellus= Erioneuron pulchellum). One of the most common introduced and now naturalized perennial grass species was bermudagrass (Cynodon dactylodon). Perennial grasses were most common along edges and on openings within the woody vegetation of the bosque. Fluffgrass was the most common of these. The most common forb was often found to be the shrublike arrowweed (Tessaria sericea); in fact, this is often regarded as a shrub. Big Bend National Park, Brewster County, Texas. June, early estival aspect. FRES No. 30 (Desert Shrub Shrubland Ecosystem). K-23 (Mesquite Bosques). SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate unit in Brown et al. (1998) which is surprising as there should be a Mesquite Series under Southwestern Interior Swamp and Riparian Scrub the same as for Seepwillow Series. No Texas ecoregion units (Griffith et al. 2004) were small enough to describe mesquite bosques. Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).

75. Bosque vegetation- An exterior view of a bosque along Alamito Creek just above its confluence with the Rio Grande. This was the outer (drier edge) of a mesquite bosque that had a relatively rich assembly of range plant species. Seepwillow or jara was visible as light green shrubs along the right margin of the photograph. Taller shrubs with darker green coloration included the natives honey mesquite, retama, and screwbean. and the invasive saltcedar. The most widespread herbaceous plant was common bermudagrass, but it occurred only in localized areas. Frequently bosques are primarily single-species stands of mesquite.This example was remarkable for its species diversity. Presidio County, Texas. June, early estival aspect. FRES No. 30 (Desert Shrub Shrubland Ecosystem). K-23 (Meesquite Bosques). SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate unit in Brown et al. (1998), but it should have been given as Mesquite Series under Southwestern Interior Swamp and Riparian Scrub. No Texas ecoregions (Griffith et al., 2004) appropriate for vegetation units this small.

76. Bosque vegetation- Interior of a mesquite bosque along the Rio Bravo in an arid region. Seepwillow or jara was prominent in the foreground. Honey mesquite was the dominant species overall and it was conspicuous in the midground. Understorey plants were mostly Eurasian cool-season annual grasses including Japanese chess and little barley. There were patches of bermudagrass. The most common native grass was the annual showy or silver fingergrass (Chloris virgata). Fluffgrass was the only native perennial grass the author could find. The relatively lush vegetation of the bosque was in stark contrast to the sparse hills of creosotebush-dominated Chihuhuan Descrub on the hills in the background. Presidio County, Texas. June, early estival aspect.FRES No. 30 (Desert Shrub Shrubland Ecosystem). K-23 (Mesqujite Bosques). SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate biotic community in Brown et al. (1998), but should have been Mesquite Series under Southwestern Interior Swamp and Riparian Scrub. No Texas ecoregions (Griffith et al., 2004) were small enough to be descriptive. Chihuhuan Deserts- Low Mountains and Bajadas Ecoregion, 24c (Griffith et al., 2004).

77. Retama (Parkinsonia aculeata) on a bosque- A localized population or stand of retama had dveloped inside the larger, overall mesquite bosque. In this particular bosque along the Rio Grande retama was the associate species to the dominant honey mesquite. Understorey was composed of cool-season annual Eurasian grass species including Japanese brome, rdd or foxtail brome, and little barley. Presidio County, Texas. June. FRES No. 30 (Desert Shrub Shrubland Ecosystem). K-23 (Mesquite Bosques). Retama variant of SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate units for biotic community in Brown et al. (1998); spatial scale too small for TExas ecoregions (Griffith et al, 2004).

78. Deep inside a bosque- Trunk of retama with dead straw of annual grasses including Japanese chess, little barley, and red brome. Multi-shoot habit designates this a woody legume as shrub, albeit a large one, and not a tree.All trunks of shrubs in this slide were retama. This was a localized stand or population of retama within the overall mesquite-dominated bosque.The gray-leafed forb was leatherweed croton (Croton pottsii) at pre-bloom stage. Presidio County, Texas. June. FRES 30 Desert Shrub Shrubland Ecosystem). K-23 (Mesquite Bosques). Retma variant of SRM 729 (Mesquite). SAF 68 (Mesquite). No appropriate biotic community given by Brown et al. (1998), but should be Mesquite Series under Southwestern Interior Swamp and Riparian Scrub. No Texas ecoregions (Griffith et al., 2004) at this small a spatial scale.

79. Retama (Parkinsonia aculeata) characteristics- Drooping branches of retama with distinctive compound leaves and inflorescence. Retama is a woody legume with a fairly large biological (species) range extending across much of southern North America. Maricopa County, Arizona. June.

80. Inflorescences of retama- Retama is in the legume subfamily, Caesalpinioideae. This subfamily has been treated by some authors as a separate family, Caesalpiniaceae. The flowers comprising the inflorescence in this group are not papilionaceous (having five fused petals) as in the Papilionoideae subfamily. Maricopa County, Arizona June.

81. Floral and foliar details of honey mesquite (Prosopis glandulosa)- Inflorescences and compound leaves of honey mesquite the dominant species of mesquite bosques. Mesquite is in the legume subfamily, Mimosoideae. Some treatments elevated this to the family level, Mimosaceae, as distinct from the Caesalpiniaceae and Papilionaceae. The latter taxon is the only one of these three subfamilies (or families) that has the papilionaceous flower consisting of five petals: two wings, two fused keels, and the banner or standard. Most authors rely on the fruit type, the legume (so-called "bean" or "pod", as the key morphological feature and which they interpret as of more taxonomic value than flower type. Erath County, Texas. May.

82. Inflorescences of mesquite- Photographs showing details of mesquite infloresences. Good example of the flower type in the Mimosoideae subfamily of the Leguminoseae. One of the virtues (there are a few, precious damn few) of honey mesquite is value as a "bee plant". Purists insist that honey made from mesquite nectar is the sweetest of all. (There are those who swear just as strongly by white clover, alfalfa, etc.). Purists of th barbeque sect feel just as strongly in favor of mesquite wood over hickory smoke for the finest in flesh food flavoring. Erath County, Texas. May.

83. Leaves and fruits of honey mesquite- Details of the compound leaf and legume fruit type in mesquite. After paying due respect to honey mesquite as a "bee plant" it should be explained that the adjective "honey" was derived from the sweet flavor of the legumes. American Indians made a bread from the meal of ground mesquite legumes and even fermented this meal into a beer (Diggs et al., 1999, p. 688). (The latter was not as effective as the whiteman's "firewater".) Sap that exudes from the fruit following injury (eg. insect damage) even has a sweet taste. Erath County, Texas. September.

84. Cattle consuming (and preparing to plant) mesquite "beans"- This photograph showed Hereford steers heartily browsing mesquite fruits. These steers had been raised on mesquite-free range and had never seen or tasted mesquite in any form until as long-yearlings they came upon this made-to-order delicacy on deteriorated black grama (Bouteloua eriopoda) range. Steers automatically began eating the fruit. Many, maybe most, of the fruits and seeds were immature so that while some seed may have been planted other seeds were removed before they could develop enough to germinate. Thee cattle were thus a form of biological brush control to some extent. These were esophageal-fistulated steers. They were used to collect forage (it fell into the canvas bag around their necks) which was then used to determine botanical and chemical composition of cattle diets on this range type (Rosiere et al., 1975; Rosiere et al, 1975). Just about "everything ever written" about mesquite described how most mammals, including man, ate mesquite fruit (either the whole fruit or just the seeds). Some of the earliest writings about mesquite explained that when animals ate the legumes the seeds (many of them at least) passed through the gastro-intestional tract undigested and were deposited at great distances from their source plant. In this way mesquite was spread on a "wholesale" scale by the white man. Early on, cattle were implicated as being agents of mesquite propagule dispersal. This means of spread became institutionalized with cattle drives and famous cattle trails. Even before the post-Civil War cattle-trailing business, sheep and goats had been trailed across much of south and west Texas and into Mexico. Thus the time-honored story goes, was mesquite spread from its pre-Columbian restriction to bosques along watercourses and habitats where natural and Indian-set fires could not travel to its "monopoly" of the range throughout the species' biological range. The story is true, at least in large part. It should also be remembered that much of this spread by livestock was by beasts of burden such as oxen along established trade routes (eg. El Camino Real from Santa Fe to Chihuhua City). What has never been fully explained is why the highly migratory North American buffalo (Bison bison) had not already spread mesquite in the thousands of years before the "white man's buffalo" became such an effective "mesquite seeder". Cessation of range fires enforced by legislation, "civilizing" agarian agriculture, and government propaganda facilitated spread of mesquite. Droughts (a feature of the climate for millenia) worked in concert with these and a "jillion" other factors perhps including small mammal "eradication" campaigns. Regardless of actual details of the "man and mesquite saga", mesquite bosques served as the natural source for much of the unnatural spread of a native species that in a remarkably short time became one of the most noxious woody plants over an immense part of North American range. New Mexico State University College Ranch, Dona Ana County, New Mexico. July.

85. Two mesquite seedlings that germinated in cattle dung- Apparently all ruminants will eat mesquite “pods” with domestic cattle appearing especially fond of them. Many rangemen have observed cattle which were so attracted to mesquite fruit that they forsook almost all other forage and browse as long as the “bean pods” were abundant. It has been long reported in the literature that consumption of mesquite fruit results in scarification and distribution of the seed in their own fertile “seedbed”. This is one factor that contributes to spread of this native invader. Buffalo (Bison bison)— among other native ruminants— undoubtedly were native dispersal agents long before the “white man’s buffalo” arrived on the scene. This fact continues to raise the unanswered question as to why there was not the mesquite “epidemic” on the virgin range. This is obviously a complex interaction of several factors, but presence of fire on the pre-white man range had to have been one of these (which is not to ignore overgrazing and all other anthropogenic influences including wholesale extermination of prairie dogs, a favorite hypothesis among pioneer Texas cattlemen). Kelton (1993, p. 79) reported accounts of early day farmers who told of their plows frequently hitting old burnt mesquite stumps as they broke virgin Texas sod.

Seepwillow (Baccharis salcifolia) Bosque

Another flood plain range cover type is the seepwillow or jara (Baccharis salcifolia)-dominated bosque. This range vegetation also develops on alluvium of deltas or other flood overflow habitats in arid and semiarid regions. Seepwillow was an associate species on mesquite bosques covered immediately above. A less common (more restricted) bosque range type is that on which seepwillow or jara is the dominant. That range cover type was treated next.

86. Seepwillow bosque- Along this gravel wash or alluvium of the Devil River seepwillow (Baccharis salcifolia) dominated a woody thicket that also consisted of (as associate species) huisache, pecan (Carya illinoinensis), and, of course, honey mesquite. Grass plants were uncommon, but species present included silver bluestem (Andropgon saccharoides= Bothriochloa saccharoides), Texas cupgrass (Eriochloa sericea), fall witchgrass (Leptoloma cognatum), red grama (Bouteloua trifida), and curly mesquite (Hilaria belangeri). Miscellaneous composites made up most of the forb group. Devil River Ranch, Val Verde County, Texas. May. FRES No. 30 (Desert Shrub Shrubland Ecosystem). No vegetation unit in Kucler (1964; in Garrison et al., 1977) or Society for Range Management (Shiflet, 1994). Seepwillow Series under Southwestern Interior Swamp and Riparian Scrub. No Texas ecoregion (Griffith et al, 2004) unit for range cover type this small in spatial scale.

87. A widely distributed, well-adapted plant (with a lot of confusing names)- Willow baccharis (Baccharis salicina= B. salicifolia= B. neglecta= B. angustifloia) has had a lot of specific epithets (hence, confusion and argument). Plants presented in these photographs and the three that follow were of willow baccharis growing on go-back rice fields on what were once coastal marshes along the Gulf Coast. The third of this set of photographs was of a young (immature) willow baccharis produced by resprouting from a cut-off mature stump. These second-season (two growing season's worth of shoot regrowth) sprouts furnished a good example of shoot characteristics of this woody composite. These sprouts are coppice shoots (often known as stump sprouts or suckers) produced by the original shoot in response to the stimulus of defoliation when the main shoot was severed. This is an example of free growth and the coppice sprouting results in heterophyllus shoots (those that were not produced from fully preformed, over-wintering buds). Stump suckers are long shoots identified and designated by long internodes (internode elongation) and absence of a cluster of leaves at shoot apex, this latter of which is a feature of short shoots (Kramer and Kozlowski, 1979, ps. 65-71, 77). Jefferson County, Texas. February.

88. Branch of willow baccharis- Upper portions of stump sprouts of willow baccharis that were introduced in the preceding photograph. Stump sprouting of a cut adult willow baccharis resulted in a young plant that had retained its leaves through winter. This individual of Baccharis salicina was growing along the Gulf Coast near mouth of Sabine River. It provided an example of young shoots, complete with foliage, of one of the most common and widely distributed species of woody composite. Jefferson County, Texas. February.

89. Shoot details of Baccharis salicina- A normal or regular leader (woody shoot) of willow baccharis on an adult plant provided a good example of bark, branching pattern, and leaf features on one of the more widely distributed woody composites along the central and western Gulf Coast and also in the Trans Pecos Basin and Range Region. A short, vertical shoot (right side in first slide; the featured subject of second slide) was shown to portray characteristic leaves. This vertical shoot originated from an established internode by developing from intercalary meristem, a phenomenon much more common following damage or death of the existing shoot (especially as from defoliation). Jefferson County, Texas. February.

90. Shrubby female in full-flower- Crown of a female willow baccharis at peak bloom. This dioecious species grows in seven of the ten vegetational (land resource) areas of Texas. This specimen, including the series of close-ups of flowers and fruit presented shortly below was growing in the West Cross Timbers. Erath County, Texas. October; full-bloom phenological stage.

91. Flowering leaders of willis baccharis- Female inflorescences show the beauty of this shrub species (and attest to its utility for landscaping making the case for more use of native plants for this purpose). Erath County, Texas. October; full-bloom phenological stage.

92. Beauty in density and in singularity- The extremely dense concentration of female flowers and the resultant striking characteristic of a female willow baccharis at peak bloom were evident in these photographs. This species seems to always put forth abundant flowers even under all-too-frequent drought. Erath County, Texas. October

93. Feminine details of willow baccharis- Units of of pistillate flowers in Baccharis salicina. Baccharis species are dioecious with disk flowers fertile and ray flowers absent forming corollas that are described as filiform (Diggs, 1999, p. 322), an adjective meaning slender or filamentous (threadlike; made up of filaments or threads) (Diggs et al., 1999, p. 1437). Erath County, Texas. October

94. Fruit of willow baccharis- Series of shots at progressively closer camera range of achenes of Baccharis salicina. Achenes, the most common fruit type of the Compositae, are single-seeded, dry, indehiscent fruits in which seed coat and pericarp (endocarp) are fused only at the funiculus, the stand uniting the ovule to its placenta (Smith, 1977, ps. 66, 296). Pappuses of long, silky bristles (Diggs et al., 1999, p. 322) are conspicuous (as evident in these photographs). Pappus refers to the cluster of plumose bristles, awns, scales, etc. at tip of achenes in Compositae and traditionally interpreted as the specialized calyx, the sepals collectively (Smith, 1977, p.303; Diggs et al., 1999, p. 1445). Achenes are preferred concentrate feeds for birds and rodents with smaller fruit often restricted to diets of smaller animal species. Abundant yields of these dry fruits is a major reason for the invasive nature of Baccharis species. B. salicina is a common woody weed on old fields, improperly managed tame pastures, and overgrazed ranges. This feature of populating abused, degraded sites and "go-back land" following abandoment from farming is basis for such common names as Roosevelt weed and New Deal weed indicating economic and drought conditions of the Great Depression and "Dirty Thirties" along with the crop "plow-under" policies of Franklin Roosevelt's New Deal. Incidentially, this species boast about as many common names as any range plant out there including consumption weed, seep-willow, groundsel-tree as well as willow baccharis. To add further confusion (and nomenclatural diversity), several of these common names (including FDR weed) are shared in common among several Baccharis species. Erath County, Texas. October

Malpais Scrub

95. Volcano Malpais Vegetation- Malpais (Spanish, mal pais for bad country) is southwestern idiom for badlands created by volcanic activity that formed rough country underlaid by basaltic lava that is usually dark, porous, and very abrasive (as on hooves). On the Carrizozo Plain one of the youngest malpais (lava flow) badlands in North America (only 1500-2000 years old) stretches for over 40 miles and supports a unique and diverse range plant community. The malpais constitutes another kind of barrens vegetation in that the basaltic lava-based environment and it’s plant life are what Nelson (1987, p. 99) defined as “primary natural community” where “primary” referred to mostly unweathered, recent, embryonic, immature, etc. parent material such as sand, rock outcrop, talus and scree, gravel bars, igneous matter. Here Mother Nature adds a twist however. The malpais habitat is a more mesic, more favorable environment for range plants because water runs off the lava surface and soaks into cracks, fissures, sink holes, crevices, etc. where accumulated water is available for plants. Thus, malpais vegetation is more mesophytic than that of adjoining non-lava habitats (Dick-Peddie, 1993, ps. 168-169). In fact, some of the shrubs and trees of the Carrizozo malpais are riparian species. Major species seen here include sotol or desert candle (Dasylirion leiophyllum), fourwing saltbush, skunkbush sumac, soaptree yucca, beavertail cactus (Opuntia phaeacantha of one variety or hybrid among some ten subspecific taxa), longleaf joint fir, canatilla, or Mormon tea (Ephedra trifurca),  sacahuiste (Nolina texana), sideoats grama, blue grama, and mesa dropseed (for starters).   Bureau of Land Management Valley of Fires Recreation Area, Lincoln County, New Mexico. June. FRES No. 33 (Southwestern Shrub Steppe Ecosystem), subunit of K-53 (Trans-Pecos Shrub Savanna) but too small to have been mapped by Kuchler (1966). No SRM for this unique range plant community. Although this range vegetation was interpreted herein as a form of scrub (= shrubland) it could be viewed as a variant of the Brown et al. (1998) unit of Mixed Grass-Scrub Series in Chihuhuan (Semidesert) Grassland biotic community.

96. Lava Flow or Volcano Malpais Vegetation- Vegetation of a kipuka which is an area of older volcano-formed land ranging in size from a few square feet to several square miles surrounded by later (more recent) lava flows resulting in an area that is more protected from fires, grazing, etc, and likely to receive more runoff water. A kipuka is an island within a larger island. The plant community in a kipuka is likely to be relict vegetation and serve as a reference area, but care must be taken in proper ecological interpretation because all malpais, and especially kipuka malpais, vegetation is probably more mesophytic than adjacent (and less protected) range plant communities.The ropy like or chocolate cake mix-looking lava is pahoehoe. Dominant species are fourwing saltbush and sotol with the same array of species as given in the preceding slide description. Note how many of these species also occurred on the gypsum dunes (eg. soaptree yucca, fourwing saltbush, skunkbush sumac) suggesting that those members of these species thriving on gypsum are gypsophilolus ecotypes of widely distributed species. Animal species (eg. reptiles like lizards) also show this ecotypic variation between the close-proximity malpais and gypsum dune ecosystems. The most ovbious variation between ecotypes of lizards living on the whitish-grey gypsum versus chocolate-brown of the malpais is in darkness of skin coloration (melanism). Bureau of Land Management Valley of Fires Recreation Area, Lincoln County, New Mexico. June. FRES No. 33 (Southwestern Shrub Steppe Ecosystem), a subunit of K-53 (Trans-Pecos Shrub Savanna) at a mapping scale smaller than that used by Kuchler (1966). No SRM specific to this unique range vegetation. This unique vegetation seemed best interpreted as a shrubland, but given unique hydric feature and more mesic root environment it could be catalogued as a variant of the Mixed Grass-Scrub Series in the Chihuhuan (Semidesert) Grassland biotic community of Brown et al. (1998). A similar lava flow vegetation in New Mexico is found in the Grants area. The Grants Malpais supports runt or stunted ponderosa pne regarded as a pygmy forest. Readers should see Dick-Peddie (1993, ps. 168-169, 173) for description of malpais habitat and vegetation and for further references on this primary land or volcanic materials vegetation. Similar volcanic badlands and vegetation is found in the Interior Northwest (eg. Idaho and Oregon).

97. Smooth sotol or desert candle (Dasyliron leiophyllum)- This member of the lily family is one of the most conspicuous shrubs of the Upper Sonoral Life Zone of the Chihuhuan Desert-Semidesert Grassland Region of southwest Texas and southern/southeastern New Mexico.It is a dioecious species but the separate male and female plants usually produce flower stalks each year. Indians used it as a fiber plant for ropes. Later, ranchers chopped it for emergency feed in drought, often as a poor man’s silage. This specimen is growing in the malpais (lava) flow of south central New Mexico as member of a relict plant community. Bureau of Land Management Valley of Fire Recreation Area, Lincoln County, New Mexico. June.

98. Inflorescence of smooth sotol or desert candle- Bureau of Land Management Valley of Fire Reacreation Area Lincoln County, New Mexico.June.

99. Sacchuiste (Nolina texana)- Sacchuiste is a common member of range plant communities from the grasslands of the Texas Edwards Plateau across to the Semidesert Grasslands and Chihuhuan Desert Region in the Trans Pecos Basin and Range Province. In the more western (and arid) portions of this region sacchuiste is more common on north slopes or deeper soils where soil moisture is higher. This large specimen is growing in the protection of the malpais flow. Sacchuiste is sometimes toxic to sheep and, especially, goats in which it causes liver and kidney degeneration (Kingsbury, 1964, p.455-456). Lincoln County, New Mexico. June.

100. High desert malpais- Lava flows in interior portions of the Pacific Northwest support malpais vegetation that is similar to that of southwestern North America, albeit usually less species-rich than that of the latter.In the High Lava Plains province just north of the Basin and Range province a weathering lava-flow Artemesia tridentata-Ribes cereum shrub community had developed. Sandberg bluegrass was the major herbaceous species and served as the community associate. Diamond Crater, Malheur National Wildlife Refuge, Harney County, Oregon. June. No FRES, Kuchler, or SRM designations. This unique and rstricted vegetation was interpreted as climax or potential natural vegetation under existing climate and stable edaphic conditions. It is part of the greater big sagebrush regional vegetation and was viewed as a variant form therein. Northern Basin and Range- High Desert Wetlands Ecoregion, 80e (Thorson et al., 2003).

101. Squaw or wax current (Ribes cereum)- Leaves and fruit of one of the co-dominants of Oregon high desert malpais. This species lacks spines and is included in the Ribesia subgenus. Diamond Crater, Malheur National Wildlife Refuge, Harney County, Oregon.June.

Black Mangrove (Avicennia nitida= A. germinans) Scrub

A mangrove unit of potential natural vegetation was recognized by Kuchler (1964) and Kuchler (1966) as Mangrove (Avicennia-Rhizophora) 105 and 96, respectively. Mangrove was mapped at the southernmost tip of the Florida Peninsula and the Key Islands and was interpreted as part of the Broadleaf Forest category of Potential Natural Vegetation. Dominants of this unit were black mangrove (Avicennia nitida= A. germinans) and red mangrove (Rhizophora mangle). Mangrove of Kuchler (1964, 1966) was included as a component of FRES No. 16 (Oak-Gum-Cypress Forest and Woodland Ecosystem), but this was not a specific nor useful unit for description and discussion of the black mangrove range type so there was no further listing of this unit. Physiogonomy of the Kuchler (1964, 1966) mangrove unit is that of forest (even if small, often dwarfish, trees). Society of American Foresters (Eyre, 1980) did not recognize a mangrove forest cover type. Black mangrove is a widely distributed species ranging from the West Indies through Central America and down along the coast of South America to Peru. When black mangrove communities are of shrub rather than tree size the plant community (and cover type) constitute shrubland or scrub not forest. Black mangrove communities in the Western Gulf of Mexico are generally of the architecture and physiogonomy of scrubland. This natural vegetation was described by Weakley et al. (2000) as Black Mangrove Tidal Shrubland and by Diammond, (1993) as the Black Mangrove Series. This natural vegetation was classified as Gulf Coastal Maritime Swampscrub 234.4, Mangrove Series, 234.41 by Brown et al. (1998, p. 47). Black mangrove scrub range vegetation (cover type) was interpreted and treated below as these fourth and fifth levels of Brown et al. (1998, p. 47).

102. Ring around the pond- Black mangrove stands had developed as climax (perhaps edaphic climax) range vegetation around the perimeter of naturally occurring saline ponds on tidal flats along the western Gulf of Mexico. This shoreland was in the general vicinity where the mouth of the Rio Grande emptied into the Gulf of Mexico. Soil conditions were saline to hypersaline and generally moist to wet with considerable variation. Dense shade of mangrove prevented development or persistence of an understorey immediately beneath the scrub, but the herbaceous plant community of tidal flats (mostly salt marshes or Southern Cordgrass Prairie) extended up to the outer edge of black mangrove scrub. This natural herbaceous range vegetation varied considerably at local scale ranging from grassland to a more mixed grass-forb community. Dominant species were generally grasses including in rough order of relative abundance: shoregrass (Monanthochloe littoralis), seashore dropseed (Sporobolus virginicus), Gulf cordgrass (Spartina spartinae), and marshhay cordgrass (S. patens), with patches of seashore or coastal saltgrass (Distichlis spicata). Shrub species that were locally common (and frequently co-dominant) with shoregrass and/or seashore dropseed included sea ox-eye (Borrichia frutescens), maritime saltwort or vidrillos (Batis maritima), and sea blite (Suaeda conferta). Dominant forbs were sea blite (S. linearis), Virginia glasswort or saladilla (Salicornia virginica), and cenicilla (Sesuvium portulacastrum). All these range plant species were halophytes. This range habitat along the shore of Gulf of Mexico was a supratidal flat, that part of the shore environment that is above regular high tides such that it is flooded (= inundated) only infrequently. Submergence of this range vegetation was uncommon. Supratidal flats are low wave action environments. The soil (rooting substrate) was primarily sand (in contrast to mud flats). Boca Chica State Park, Boca Chica subdelta (of the greater Rio Grande Delta), Cameron County, Texas. February, late hibernal or early vernal aspect. No FRES No. seemed appropriate or descriptive. K-96 by Kuchler (1966). No SRM or SAF. Gulf Coastal Maritime Swampscrub biotic community 234.4, Mangrove Series 234.41 of Brown et al. (1998, p. 47). Western Gulf Coastal Plain- Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).

103. Mangrove pond- Black mangrove formed an exclusive stand around this natural saline pond on one of many tidal flats of the Rio Grande Delta. This pond (and several others) was surrounded by coastal Southern Cordgrass Prairie dominated by Gulf cordgrass or sacahuiste (Spartina spartae) with shoregrass and seashore dropseed as associate species. This climax grassland community extended to the outer edge of black mangrove stands (also climax range vegetation) but not as an understorey in these localized scrublands. This coastal shore range community was on a supratidal flat meaning that it was above usual high tides such that this vegetation was partially submerged only at infrequent intervals. Boca Chica State Park, Boca Chica subdelta (of greater Rio Grande Delta). Cameron County, Texas. February, late hibernal or vernal aspect. No FRES was specific to this shrubland; no SAF or SRM. Gulf Coastal Maritime Swampscrub biotic community 234.4, Mangrove Series 234.41 of Brown et al. (1998, p. 47). Western Gulf Coastal Plain-Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).

104. Ecotone at a small scale- At scale of microsite or microhabitat a Southern Cordgrass Prairie community and black mangrove scrubland were engaged in a "struggle for existence" and formed a transition zone of native range vegetation. Shoregrass and, secondarily, seashore dropseed and saladilla or Varginia glasswort of the Gulf coastal tallgrass (or, physiogonomically, mixed) prairie had advanced to the perimeter of a black mangrove stand that was so dense as to exclude other vascular range plants. This range ecotone writ small was on banks of numerous small, natural, saline ponds on tidal flats of the Boca Chica subdelta of the Rio Grande Delta. Cameron County, Texas. February, later hibernal aspect. There was not a FRES specific to black mangrove shrubland. Neither was there an SRM or SAF cover type. Shown by Brown et al. (1998, p. 47) as Gulf Coastal Maritime Swampscrub 234.4, Mangrove Series 234.41. Western Gulf Coastal Plain-Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).

105. Black mangrove scrub- On an intratidal (or, sometimes, intertidal) mud flat black mangrove formed an extensive community that was such a "pure" consociation as to be more like a population of this species (ie. a nearly single species-stand resembling an agronomic or horticultural monoculture). Intratidal flats are coastal shore habitats that are defined as very frequently flooded or inundated (in contrast to supratidal flats that are infrequently flooded due to being above--higher in elevation--regular high tide and subtidal flats that are below low tides). Mud flats, like salt marshes, are low wave action environments, but the smaller soil separates of silt and clay rather than coarse-grained sand form the soil or rooting substrate. General (and characteristic) physiogonomy and architecture of this range plant community was shown in these two slides. This vast stand of coastal scrub was essentially a single-species community or, perhaps more precisely, a population. There were almost no plants of other species within or beneath canopy of black mangrove. Other species of shore plants were limited to the perimeter of this extensive mangrove stand so that status or rank of plant community would probably have to include all plant species growing on the mud flats. Other such range species were shown in photographs later (below) in this series. South Padre Island, Cameron County, Texas. February, late hibernal aspect. There were no specific FRES, SAF, or SRM designations for black mangrove. Likewise potential natural vegetation units 105 and 96 of Kuchler (1964, 1966, respectively) were shown as specific only to south Florida. The black mangrove (Avicennia nitida= A. germinas) form of Kuchler's mangrove (Avicennia-Rhizophora) in the western Gulf of Mexico was a vegetational "island" apparently of such small size or limited areal extent as to be unmappable at Kuchler scales. Gulf Coastal Maritime Swampscrub biotic community 243.4, Mangrove Series 243.41 of Brown et al. (1998, p. 47). Western Gulf Coastal Plain- Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).

106. Advancing legions of black mangrove- Leading edge of a black mangrove shrubland on an intratidal (= intertidal) mud flat with aerial roots or pneumatophores rising conspicuously from soil in foreground. Black mangrove forms vast systems of cable roots which produce pneumatophores (Odum and McIvor in Myers and Ewel, 1990, p. 523). Pneumatophores are vertical aerial roots defined as "specialized 'breathing' roots[s] developed in some plant species that grow in waterlogged or strongly compacted soils, e.g. mangroves" (Allaby, 1998). There were no other plant species growing in (under) or along the perimeter of this black mangrove stand. Black mangrove was regarded by Snedaker (1982) as shade tolerant and sun intolerant when immature while becoming shade intolerant at maturity. As a result of these conditions, adaptations, and probably numerous unknown factors black mangrove characteristically exists as single species-stands. Similarly, all mangrove species hav been viewed as fire-intolerant so as to be threatened by intense fires (Wade et al., 1990). Fire exclusion from mangrove stands is another likely factor responsible for lack of botanical diversity of these range plant communities or populations. South Padre Island, Cameron County, Texas. No FRES, SRM or SAF designations. Gulf Coastal Maritime Swampscrub biotic community 243.4, Mangrove Series 243.41 of Brown et al. (1998, p. 47). Western Gulf Coastal Plain- Laguna Madre Barrier Islands and Coastal Marshes Eeoreigon 34i (Griffith et al., 2004).

107. A local "frontier" of black mangrove- A transverse view along the perimeter of a black mangrove shrubland on a intertidal (= intratidal) mud flat of the western Gulf of Mexico illustrated the single species compositional feature of this range cover type.The solitary shoot or single plant beyond the mangrove stand is an advance guard of this species as it "marches" inland on the mud flat from the existing edge of the mangrove stand. It was not determined if this was a seedling (an immature unique genetic individual) produced sexually or a far-ranging asexual module or ramet of an existing genetic individual plant. Detail of the bare soil of this very frequently flooded zone of Gulf of Mexico and dispersion of black mangrove propagules thereon was presented in the immediately succeeding slide. South Padre Island, Cameron Texas. February, late hibernal aspect. No meaningful FRES; no SRM or SAF. Gulf Coastal Maritime Swampscrub biotic community 243.4, Mangrove Series 243.41 (Brown et al., 1998, p. 47). Western Gulf Coastal Plain- Laguna Madre Barrier Islands and Costal Marshes Ecoregion 34i (Griffith et al., 2004).

108. "Frontier" of black mangrove up close (but not dangerous)- Bare soil (at least, rooting medium) of intertidal (intratidal) mud flat with black mangrove propagules well-despersed thereon in foreground. Advancing edge of black mangrove scrub in background. Smaller shoots at leading perimeter of mangrove stand were modules, ramets, or clones of established mature plant(s) of the mangrove stand. South paedre Island, Cameron County, Texas. February, late hibernal aspect.

109. "Seeds" of the next generation- Close-up view of black mangrove propagules on the intertidal mud flat shown in the preceding two photographs. Black mangrove reproduces both sexually and asexually. Sexual reproduction is by vivipary in which the embryo begins germination and has continuous embryonic development while fruit is still on the parent plant. Absence of an inactive stage in the embryo and general mangrove organ that forms from sexual fertilization renders the term seed inappropriate so that propagule is the more precise and preferred term (Odum and McIvor in Myers and Ewel, 1990, p. 525). The other special adapatation for sexual reproduction in mangrove species is hydrochory (means of dispersion in which water is the agent that transports the propagule). These two adaptations of sexual reproduction enable mangrove species to disperse and establish seedlings over large areas and to do so quickly. South Padre Island, Cameron County, Texas. February.

110. "Brush skirmish" of tidal flat range vegetation- An ecotone of an herbaceous salt marsh vegetation and a black mangrove stand on an intratidal (= intertidal) mud flat in the western Gulf of Mexico. Within the same stand of black mangrove scrubland shown in prededing photographs but on slightly higher ground and with sparser cover of mangrove an herbaceous range community of shoregrass and Virginia glasswort or saladilla with lesser cover of maritime saltwort or vidrillos had developed. This transition zone was similar to that on supratidal flats of sandier substrate shown above. South Padre Island, Cameron County, Texas. February, late hibernal or early vernal aspect. No descriptive FRES. No SRM or SAF for black mangrove. Gulf Coastal Maritime Swampscrub biotic community 243.4, Mangrove Series 243.41 of Brown et al. (1998, p. 47). West Gulf Coastal Plain- Laguna Madre Barrier Islands and Coastal Marshes Ecoregion 34i (Griffith et al., 2004).

111. Herbaceous combatants on a tidal flat- Detail of salt marsh vegetation shown in the immediately preceding photograph. Principal species were shoregrass, Virginia glasswort or saladilla, and maritime saltwort or vidrillos. South Padre Island, Cameron County, Texas. February, late hibernal or early vernal aspect.

112. Leader of black mangrove (Avicennia germinans= A. nitida)- Main branch off black mangrove shoot showing leaf pattern. Boca Chica State Park, Boca Chica subdelta (of greater Rio Grande Delta), Cameron County, Texas. February.

113. Shoot apices of black mangrove- Details of shoot tips, including leaves (complete with salt incrustations), of black mangrove growing around a natural saline pond on a Gulf Coast tidal flat. Shoots of shoregrass were growing with black mangrove and were clearly visible. Boca Chica State Park, Boca Chica subdelta (of greater Rio Grande Delta) Cameron County, Texas. February.

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