Shortgrass Prairie

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The shortgrass plains usually have been interpreted as either the most xeric form climax grassland on the Great Plains or as a grazing disclimax (with other compounding disturbances and other variables). The title of shortgrass plains for this semiarid Great Plains grassland can be traced back to Clements (1920, p. 139) who interpreted it as the Bulbilis-Bouteloua Association, a sod grassland of grama and buffalograss in which blue grama (Bouteloua gracilis) was "the chief dominant throughout" (Clements, 1920, p. 140). Kuchler (1964) and on map accompanying Garrison et al. (1977) regarded the shortgrass country as potential natural vegetation, mapping unit 58, Grama-Buffalo grass (Bouteloua-Buchloe). The shortgrass plains were interpreted herein as climax range vegetation and therefore given separate treatment. Definitive source for shortgrass prairie, especially from an ecosystem view, is Lauenroth and Milchunas (in Coupland, 1992, ps. 183-226) and Lauenroth and Burke (2008) although the latter encompassed--unavoidably--overlapping units of mixed prairie as well as shortgrass grazing disclimax and adjoining units of other potential natural (= climax) vegetation (next paragraph). Hence, the area shown as shortgrass steppe in Lauenroth and Burke (2008, figures on ps. 4-26 passim) was mapped broader and more general than was the actual situation. Shortgrass plains grassland is the climax range vegetation over much of the western portion of the Great Plains physiographic province, including Southern Great Plains (= High Plains, Llano Estacado), Central Great Plains, and Northern Great Plains. Names of some of the ecoregions within this vast region (Chapman et al., 2003; Woods et al., 2005; Chapman et al., 2006) did not always confer readily this areal extent or the fact that the ecoregions are part of the Great Plains province. 

Precise boundaries of shortgrass (plains) prairie are impossible to define/delineate because dynamics of grassland vegetation result in shifting of range plant communities over time and space (frequently at relatively short and small scales) and due to the condition of inconsistent, if not somewhat arbitrary, designation and criteria on which designations have traditionally been based. Shortgrass-dominated grassland, particularily the blue grama-buffalograss type, occurs as part of a vegetational mosaic, a patchwork of climax plant communities, along with mixed prairie, postclimax (= edapho-topographic climax) tallgrass prairie and/or tallgrass-shrub savanna, foothill Juniperus-Pinus woodlands, and open understorey conifer-grass forests (Lauenroth and Burke (2008, ps. 4-7, 70-83, 389-446).

 
1. Mesa and plains grassland- Shortgrass plains or shortgrass form of mixed prairie depending upon interpretation and which classification of vegetation types is used. Besides blue grama and buffalograss, galleta (Hilaria jamesii) rounds out the three dominant species. Several species ofthreeawn such as Aristida purpurea and A. longiseta are present but mid-grasses like western wheatgrass, sideoats grama, and siver bluestem are absent. Cholla (Opuntia imbricata) lends a savanna-like aspect to this shortgrass country and serves as an emergency feed source in drought if spines are burned off with propane burners. Peak estival aspect, June.Quay County, New Mexico. FRES No. 38 (Plains Grasslands Ecosystem). K-58 (Gramagrass-Buffalograss). SRM 502 (Grama-Galleta). Southwestern Tablelands- Semiarid Canadian Breaks Ecoregion, 26d (Omernik and Griffith, 2006).
 
2. Characteristic topography of the Southern Great Plains or Southern High Plains (the Llano Estachato or Staked Plains)-Blue grama, buffalograss, galleta, vine mesquite. Note the broad-leafed milkweed (Asclepias spp.).This is the strong grass country which frontiersman found to their pleasant surprise “cured on the vine” (retains its nutritive value during dormancy).Guadalupe County, New Mexico. June. FRES No. 38 (Plains Grasslands Ecosystem). K-58 (Gramagrass-Buffalograss). SRM 715 (Grama-Buffalograss). Southwestern Tablelands- Conchas/Pecos Plains Ecoregion, 26n (Omernik and Griffith, 2006).
 
3. Classic example of shortgrass plains of almost exclusive cover of blue grama and buffalograss- Some red threeawn and galleta. July of a drought with no rain for 2 months following a wet winter. Prowers County, Colorado. FRES No. 38 (Plains Grasslands Ecosystem). K-58 (Gramagrass-Buffalograss). SRM 715 (Grama-Buffalograss). Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).
 
4. Another view of shortgrass grassland- Besides the buffalograss and blue grama, squirreltail bottlebrush (Sitanion hystrix) is a major species. Laramie Plains, Albany County, Wyoming.  July.  FRES No. 38; K-58 (Gramagrass-Buffalograss). SRM 715 (Grama-Buffalograss). Wyoming Basin- Laramie Basin Ecoregion, 18f (Chapman et al., 2003)
 

5. Shortgrass plains- This was an example of the shortgrass phase or shortgrass community form of mixed prairie. Blue grama and buffalograss were the two dominants of this climax grassland, but western wheatgrass, sideoats grama, and sand dropseed (the classic mid-grasses) were also common while silver bluestem formed distinct colonies (eg. the light tan area in left mid-ground) and individual plants of the cespitose little bluestem were also present. Dominant forb was wild alfalfa. This combination of sod-forming grasses and bunchgrasses is characteristic of mixed prairie, but the predominant sod-grasses were responsible for the shortgrass physiogonomy of this Southern High Plains grassland. The community more typical of mixed prairie (more species-rich) was featured in the foreground to show the biological diversity of plains grassland, but the less diverse blue grama-buffalograss community of the background was the more common community on this cattle range.

Commanche National Grassland, Baca County, Colorado. Estival aspect, July. FRES No. 38 (Plains Grassland Ecosystem). K- 61 (Wheatgrass-Grama-Buffalograss) in foreground; K-58 (Grama-Buffalograss) in background. SRM 715 (Grama-Buffalograss). Hardland range site. Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

 

6. High Plains grassland- This was another example of the shortgrass physiogonomy form of mixed prairie. Blue grama, buffalograss, and galleta (in that order) were dominant species though mid-grass species were common (western wheatgrss, sideoats grama, sand dropseed, and Indian ricegrass were well-represented while prairie junegrass was present but infrequent in this sward). Common plains yucca or soapweed yucca was present as the major forb, but it was more conspicuous than it was common. Widely scattered (barely present) shrubs were cholla and four-wing saltbush.

Crowley County, Colorado. July. Estival aspect, July. FRES No. 38 (Plains Grassland Ecosystem). K- 58 (Grama-Buffalograss). SRM 715 (Grama-Buffalograss). Loamy Plains range site. Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

 

7. Shortgrass plains- This landscape was included to show viewers the classic blue grama-buffalograss community interpreted by many prairiemen as a shortgrass disclimax (a grazing or zootic disturbance climax). Beginning range students are referred to Weaver and Albertson (1954, ps. 19-25). The two shortgrass species "have a monopoly" on the plant-growing resources of this ecosystem. As with the grassland communities seen in preceding slides such species as western wheatgrass, sideoats grama, and galleta were also present. Threeawns (Aristida species) were very rare while shrubs and even forbs were non-existant for all practical purposes. Textbook example of shortgrass plains grassland.

From the collection of examples presented here the most ardent plainsmen and fans of the "shortgrass country" can understand why plains-weary travelers (and some "foreigners" not so travel-weary) find this landscape so monotonous and boring. To the true plainsman, however, it is "God's Country" and the finest place on Earth.

Elbert County, Colorado. Estival aspect, July. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 715 (Grama-Buffalograss). Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

 

8. Drought-smitten shortgrass plains- Southern High Plains grassland on which potential natural (climax) vegetation is domination by blue grama and buffalograss with substantial cover of sideoats grama, sand dropseed, and even some silver bluestem. This deteriorated range had been degraded to a nearly "solid" or "pure" stand of buffalograss, a grazing disturbance climax. Some cover of blue grama occurred in isolated patches. There were enough, even more widely isolated individual plants of sideoats grama (all of them had received heavy to extreme degree of use) to indicate that this midgrass was an associate species and, therefore, that the potential natural vegetation of this range was a mixed prairie with a clear predominance of shortgrass species.

This author had periodically observed this particular cattle range over a period of 40 years. It was consistently managed under (with) heavy grazing during that span of time. It remained a buffalograss disclimax with almost no change of any sort in species composition, physiogonomy, etc. Even under this heavy defoliation buffalograss had maintained the cover and density of shoots shown here. A few plants of wild alfalfa or slimleaf scurfpea comprised the forb component of this disturbance climax. There were some Yucca glauca plants (at the general size, cover, and density shown in the second photograph) so that this was the major shrub species. Plains pricklypear was the second most common shrub. There were also a few plants of the subshrub, broom snakeweed.

This range was destocked (and had been for some time) when these photographs were taken. A cattle range adjacent to (conterminous with) the range shown here was current stocked with beef cattle that were being maintained with survival feeding (shown and explained below). Question: what, if any, affect would presence of cattle on this range under these feed and plant-growing conditions (survival feeding, drought-induced dormancy) have on this range vegetation?

At time of these photographs the impacts of eight straight years of drought, culminating in Exceptional Drought (the condition shown in slides) was being manifest. Exceptional is the highest or worst category of Drought Severity Classification (Palmer Drought Index of -5.0) used by the US Drought Monitor program. These photographs bespoke of the grazing resistance and drought tolerance of buffalograss.

Cimarron County, Oklahoma. Late June; early summer with plants in drought-dormancy. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 715 (Grama-Buffalograss) and/or SRM 611 (Blue Grama-Buffalo Grass): both of these rangeland cover types (Shiflet, 1994, ps. 93-94, 79-80, respectively) included the High Plains region of Oklahoma, Texas, and New Mexico in their descriptions. Grama "Short-Grass" Series, 142.12 of Plains Grassland biotic community, 142.1 (Brown et al., 1998, p. 40). Deep Hardland range site. High Plains- Moderate Relief Plains Ecoregion, 25c (Woods et al., 2005).

 

9. Two range sites in High Plains drought- Two range sites in the Southern High Plains: Deep Hardland (foreground) and a Breaks (background) range site in the background under conditions of Exceptional Drought. This range and its vegetation was in the same cattle pasture described in the immediately slides and caption. The Deep Hardland site is a simple shortgrss (plains) prairie, the climax vegetation of which is blue grma-buffalograss as con-dominants with sideoats grama as associate species. Plants of sideoats grama had been grazed to down to the height as that of buffalograss. This range plant community had been been depleted to a single species stand (a population) of buffalograss. Such range vegetation would probably be most accurately described as a anthropogenic (man-induced) disclimax, a zootic disclimax in which cattle-grazing caused almost complete replacement of blue grama, the potential dominant, and sideoats grama, the natural associate, by buffalograss, the lesser co-dominant in the climax range vegetation.

The Breaks range site was dominated by skunkbush sumac (Rhus trilobata= R. aromatica) odorata). Otherwise, plant species present were the same as on the Deep Hardland site though with noticeable more sideoats grama. Cattle had grazed the range vegetation of this low Breaks site. Currently no cattle were on this range under the conditions of Exceptional Drought that were explained in the preceding caption.

Cimarron County, Oklahoma. Late June; early summer with plants in drought-dormancy. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 715 (Grama-Buffalograss) and/or SRM 611 (Blue Grama-Buffalo Grass): both of these rangeland cover types (Shiflet, 1994, ps. 93-94, 79-80, respectively) included the High Plains region of Oklahoma, Texas, and New Mexico in their descriptions. Grama "Short-Grass" Series, 142.12 of Plains Grassland biotic community, 142.1 (Brown et al., 1998, p. 40). High Plains- Moderate Relief Plains Ecoregion, 25c (Woods et al., 2005).

 

10. About as bad as it gets- Degraded shortgrass plains range that is essentially a single-species stand of buffalograss in a drought ranked as Exceptional, the worst or highest rating on the Drought Severity Classification scale (Palmer Drought Index of -5.0). Beef cattle were being fed emergency. This cattle range was adjacent to the destocked cattle range described in the preceding two photo-captions.

This herd was being kept alive by maintenance feeding, the practice of providing a balanced ration (complete diet) to livestock for prolonged periods as in extended drought. Cattle were essentially getting "next to nothing" from the remaining range herbage (it was too short for them to be able to eat much of it). Under this situation what, if any, impact would continued cattle stocking have on this range? Cattle were in effect being kept on this rangeland rather than paying out additional expense of moving (as by shipping or trailing) them to a dry lot. Or said another way, cattle were being dry lotted on the range where they were fed a maintenance diet rather than either paying to rent a lot or paying to have them fed (or, alternatively, to sell the herd). Given that range plants were in drought-dormancy and there was no feed left for cattle on the range (they could not remove anymore plant material by eating) did range-retention of cattle induce damage--and if so, how much--to the land and/or plant life? Other than damage by trampling or dunging, which could have been slight to considerable, the answer is that continuing to keep non-grazing cattle on the range most likely had limited adverse impact. Once buffalograss, about the only plant species present, started to green up "if and when it rained again", continuing to stock cattle could have a detrimental influence if grazing exceeded feeding (immediate grazing) capacity of the range (ie. stocking during plant recovery resulted in overuse of regrowing buffalograss).

Management of ranch resources (range, livestock, financial, internal structures, labor, equipment, etc.) under adverse situations is an art form based on rational financial, scientific, cultural, etc. factors. This is risk management in ranching. Drought is the great risk in in sermiarid regions such as the Great Plains.

Cimarron County, Oklahoma. Late June; early summer with plants in drought-dormancy. FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 715 (Grama-Buffalograss) and/or SRM 611 (Blue Grama-Buffalo Grass): both of these rangeland cover types (Shiflet, 1994, ps. 93-94, 79-80, respectively) included the High Plains region of Oklahoma, Texas, and New Mexico in their descriptions. Grama "Short-Grass" Series, 142.12 of Plains Grassland biotic community, 142.1 (Brown et al., 1998, p. 40). High Plains- Moderate Relief Plains Ecoregion, 25c (Woods et al., 2005).

 
 

11. Blue grama grassland in the worst of drought- A consociation of blue grama in the Raton section of the Great Plains province with large plants so large that they had semi-sodforming bases. This was the appearance of a destocked range at beginning of the third year into a drought that measured Extraordinary (the highest or most severe category of the Palmer Drought Severity Index). The author did not know when cattle had been taken off this range, but no livestock had grazed it any during the current warm-growing season.

There were trace amounts of both western wheatgrass and buffalograss in this grassland vegetation with first one and then other of these two species having somewhat more cover and shoot density. This was essentially a "pure" stand (population) of blue grama with an occasional local group of cholla cactus plants that averaged about two or three plants per acre. Interestingly enough there were relatively few plants of plains pricklypear in this range plant community. Cholla did not have density or cover enough to come close to qualifying as a savanna, but there clearly was a woody plant component--sparse though it was--to this climax range vegetation. There were also widely scattered plants of soapweed yucca (Yuccca glauca) though it was so dry they didn't dare bloom.

A range just across the fence in lower range condition (Good condition class) had some plants of bottlebrush squrreltail, red threeawn, and sand dropseed. This range had more species diversity, but these were increasers or invaders (for this range site) so that range was in lower successional status.

Huerfano County, Colorado. Late June (early estival aspect in Extraordinary drought). FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611 (Blue Grama-Buffalo Grass) and/or 715 (Grama-Buffalograss). Grama "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

 

12. Droughted out, but not droughted away- Sward of a consociation of blue grama in the Raton section of the Great Plains physiographic province. Two "photoquadrants" of the range vegetation introduced in the two immediately preceding photographs. Almost all herbage was that of blue grama with limited cover of buffalograss and western wheatgrass and less cover yet of red threeawn. The latter was an increaser on this range site while the former two were decreasers and could be regarded as associate species with slightly more cover and shoot density of one or the other grasses varying at local scale. At peak flowering time for both buffalograss and western wheatgrass, but essentially all plants (of all species except cholla cactus) were in drought dormancy. This range had been suffering from Extraordinary drought (worst category as measured on the Palmer Drought Severity Scale) for this and the preceding growing season. It had been destocked (except for free-ranging wildlife such as pronghorn) at some point the previous year and had zero livestock grazing so far in the current growing season. From looking at remaining (dead) sexual shoots remaining from last year and its Extraordinary drought this range had not been grazed for the past two growing seasons.

Recent light rains had moistened the soil surface enough to bring about green-up of basal shoots with leaves looking fairly vigorous. Amazing what the native plants can do in the harshness of this drought-prone semiarid environment.

Beginning students should not confuse range feed condition with ecological range condition class. Rough though this range looked as to current feed conditions (not enough herbage to profitably sustain livestock grazing) it was in Excellent range condition class being the climax vegetation (the range plant community was probably in as high an ecological/successional status as the pristine range under buffalo grazing).

Huerfano County, Colorado. Late June (early estival aspect in Extraordinary drought). FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611 (Blue Grama-Buffalo Grass) and/or 715 (Grama-Buffalograss). Grama "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

 

13. Grassland with two botanical masters and a high-ranking lieutenant- Great Plains grassland co-dominated by blue grama and galleta and with cholla cactus as an associate. Another shortgrass plains grasslant tending to a mixed prairie on the Raton section of the Great Plains. Like the preceding range, this one was in Excellent range condition class even though it was suffering from the stress of Extraordinary drought (as ranked on the Palmer Index). In this climax range vegetation cholla (again, as in the preceding example) was not present at relative proportions (cover, density, general aspect abundance) sufficient to be interpreted as a savanna. Cholla is as native as the co-dominant eragrostoid grasses and all species were in general rank of abundance as to be representative of the potential natural vegetation.

There were some widely scattered patches of the rhizomatous western wheatgrass and stoloniferous buffalograss that formed local "sod carpets". There were quite a number of plants of the cespitose red threeawn which was probably an increaser on this range site/type. Sand dropseed--as would be expected--was present, but just enough to mention. There were very few isolated plants of wavyleaf thistle (Cirsium undulatum). Otherwise this was a rather simple range plant coummunity.

Pueblo County, Colorado. Late June (early estival aspect in Extraordinary drought). FRES No. 38 (Plains Grassland Ecosystem). Variant of K-58 (Grama-Buffalograss). SRM 705 (Blue Grama-Galleta). Grama "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

 

14. Shrubs on grassland in right proportions- A local group of cholla catctus plants growing on the blue grama-galleta grassland range preented in the preceding slide. In this climax range vegetation cholla typically grew in groups of four to six or seven individual plants. Apparently some of these were the sexual progeny of others. This seemed to be the generational relationship based on some plants being substantially larger (so presumedly older) than others. Smaller plants grew at such distance from larger ones (roughly two to three feet) that the possibility of clonal plants (offshoots or modules) was ruled out.

Instead it seemed obvious that individual plants were unique genotypes arising from bountiful fruit-seed production. Such a heavy seed crop seemed on its way for the current year based on super-abundant inflorescences such as shown here. Of course, cactus flowers are so colorful anyway. There is remarkable beauty in the shortgrass country if one chooses to see it.

Pueblo County, Colorado. Late June (early estival aspect in Extraordinary drought). FRES No. 38 (Plains Grassland Ecosystem). Variant of K-58 (Grama-Buffalograss). SRM 705 (Blue Grama-Galleta). Grama "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

 

Organization note: in close proximity to the examples of blue grama and blue grama-galleta ranges on drier uplands that were presented immediately above there were ranges at slightly lower elevations (lower topographic features) and deeper soils dominated exclusively by galleta and exclusively by alkali sacaton (ie. consociations of these singular species). These lowland range cover types were shown near the beginning (top) of this chapter in order to "pen" examples of range types together (ie. organization was by range type not geographic location or spatial occurrence of range plant communities). However, the viewer can still get a sense of this range vegetation "organization" (patterns of the various range types and sites) at landscape scale by "galloping" back to start of the circle and quickly finding the examples by county (Pueblo and Otero Counties, Colorado in this instance).

These upland range types together with the two more lowland types constituted a spatial alignment of range plant communities along a catena or toposequence. A toposequence is a sequence of soils (series and/or associations) that developed along a topographic gradient under similar climate and parent material and that are of similar ages so that most differences in these soils is due mostly to relief. These differences in soils correspond to different range sites with the result that differences in potential natural (climax) range vegetation are due primarily to edaphic variations.

The arrangement of range cover types aligned along the catena can be seen by viewing the above galleta-dominated range and alkali sacaton flat with the two range types presented immediately above.

 

15. If it ain't drought; its prairie dogs- "Dog town" of blacktailed prairie dog on a (former) blue grama-buffalograss-western wheatgrass mixed prairie range. This particular grazing unit was cut into a relatively small pasture of an odd size so that grazing by livestock had been curtailed long ago. Blacktailed prairie dogs moved in and they, with exception of a few blacktailed jackrabbits (Lepus californicus), and pronghorn, were the only mammalian herbivores. Prairie dogs degraded this former mixed prairie into a weed patch of field bindwed (Convolvulus arvensis) and tansy leaf aster (aster tanacetifolius). The aster is an annual composite while the bindweed is a perennial morning-glory. Both are native to this region, but are also particularily noxious weeds and pioneer species of severely degraded ranges, old fields, abandoned schoolyards, roadcuts, etc.

Common experience (even cursury observations) have shown common field bindweed to be quite palatable to many animal species including cattle. Blacktailed prairie dogs also feed on field bindweed, but it is so aggresive and competitive that it manages to survive under extremely heavy prairie dog use.

This author ws not privy to the history of this particular piece of rangeland other than to be inforrmed that prairie dogs had been established on it for a number of years, and that it had been depleted to this pioneer plant stage for a long time. This depleted range served as an example of how native fauna can overgraze and degrade natural range vegetation. It appears that nobody today can provide a rationale explanation as to why in the earliest time of white man records blacktailed prairie dogs had not devestated thousands or even hundreds of thousands of acres of Great Plains grassland to the degree of ranage depletion that--as shown in this example--extensive colonies of this fossorial (burrowing; ground-dwelling) rodent havee caused in contemporary times. Perhaps in days of the virgin range blacktailed prairie dog populations were forced to move more frequently when and where there were more natural predators, free-ranging native herbivores (from buffalo to prairie dogs to gophers to elk), and no artificial (human) barriers like roads, irrigation cannels, fenced pastures, and cultivated fields. All such speculation noted (and then set aside), it must be remarked objectively that under many human impacts blacktailed prairie dogs have frequently (typically, perhaps) been overgrazing and degrading ranges to such extent that the white man has waged war via poisoning campaigns against these native rodents for well over a century.

Even the most cursory view of this range revealed that has been degraded to the lowest possible seral stage above bare soil. These two photographs provided the answer to the question, Why have stockmen been so relentless in their destruction of the blacktailed prairie dog. Again, scenes of devestated range like this may have been much been rare to very confined prior to man's arrival on North American range. (Incidentially, that includes the redman who, although of much earlier arrival, is no more native than the now-predominant white race.) God alone knows the answer to this ecological riddle. What we know now is what we see.

Otero County, Colorado. Late June (early estival aspect; peak bloom stage of the two range forbs). FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611 (Blue Grama-Buffalo Grass) and/or 715 (Grama-Buffalograss). Grama "Short-Grass" Series of Brown et al. (1998). Southwestern Tablelands- Piedmont Plains and Tablelands Ecoregion, 26e (Chapman et al., 2006).

 
The following section was developed from Central High Plains grassland on the Central Plains Experimental Range (Agricultural Research Service) in Weld County, Colorado. Range types on this large experimental range varied from classic mixed prairie dominated by needle-and-thread (Stipa comata) that developed as postclimax on sandhills of the Central Great Plains through upland mixed prairie of both shortgrasses (notably blue grama and buffalograss) and mid grasses (western wheatgrass, needle-and-thread, and sideoats grama) down to textbook buffalograss-blue grama shortgrass plains climax vegetation on "tight land" (= soils of finner texture or, in other words, of higher clay and lower content sand content). Taken in totality (as a whole unit) the Central Plains Experimental Range was interpreted and described as "Shortgrass Steppe" (Lauenroth and Burke, 2008). Obviously this broad-brush designation was an oversimplified, sterotypic description, but those parts of this experimental range (and some rangeland on adjoining land) was classic "shortgrass country". Such range vegetation was treated immediately below.
 

17. Grazing disclimax of mixed prairie- A mixed prairie dominated by needle-and-thread with Indian ricegrass as associate converted into a buffalograss-blue grama short grass (co-dominants) disturbance climax by longtern overgrazing by cattle. The associate grass species was sixweeks fescue, a native annual festucoid species. The conspicuous yellow composite was stiff greenthread (Thelosperma filifolium var intermedium) and the white infloresences were on pale or white evening-primrose (Oenothera albicaluis) an annual.member of Onagraceae. (Both of these forbs were shown below with other species from this area.)

Weld County, Colorado. Mid-June (late vernal aspect). FRES No. 38 (Plains Grassland Ecosystem). Mixture of K-57 (Grama-Needlegrass-Wheatgrass) and K-58 (Grama-Buffalograss). SRM 608 (Wheatgrass-Grama-Needlegrass). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13,, High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

18. Disturbed carpet- Sward of buffalograss-blue grama disturbance climax that replaced a needle-and-thread-dominated mixed prairie tht was the potential natural plant community (climatic climax). View of sward on the shortgrass disclimax introduced immediately above. In addition to the co-dominants other major species included sixweeks fescue, the associate grass, and stiff green thread and pale evening-primrose, the two most abundant forbs on this range. There were a few closely cropped plants of neeedle-and-thread, but the author could not find any Indian ricegrass (none of sufficient size to be identifiable anyway).

Note: range vegetation presented in this and the preceding photograp were typical or representative samples of the overgrazed range. They were not in a sacrifice area. More on this important point in the immediately following caption.

Weld County, Colorado. Mid-June (late vernal aspect). FRES No. 38 (Plains Grassland Ecosystem). Mixture of K-57 (Grama-Needlegrass-Wheatgrass) and K-58 (Grama-Buffalograss). SRM 608 (Wheatgrass-Grama-Needlegrass). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

19. What was before (or The fence made the difference)- Relict needle-and-thread--dominated mixed prairie (Indian ricegrass was associate species) on the other side of the fence from the buffalograss-blue grama disturbance climax shown in the two immediately preceding slides. Buffalograss, blue grama, and sixweeks fescue were also common and important members of this protected strip of grassland, but the fence separated climax bunchgrass mixed prairie from disclimax shortgrass. Overgrazing (longterm overuse), by cattle in this case, was responsible for this range type conversion.

The two most common forbs in the exclosure were stiff greenthread and pale evening-primrose the same as in the overgrazed pasture. Pale evening-primrose appeared to be about as abundant on one side of the fence as the other, but stiff greenthread was clearly much denser and of greater cover on the overgrazed range.

Specification: there was a ranch road that ran alongside the fence on the overgrazed range (visible in both of the photographs described in this caption). The immediately preceding photographs of this shortgrass disclimax were not taken either in or adjacent to the ranch road, but rather out in representative portions of the overgrazed range. Range vegetation presented in the two above slides was not in the sacrifice area of the ranch road.

Weld County, Colorado. Mid-June (late vernal aspect). FRES No. 38 (Plains Grassland Ecosystem). Mixture of K-57 (Grama-Needlegrass-Wheatgrass) and K-58 (Grama-Buffalograss). SRM 608 (Wheatgrass-Grama-Needlegrass). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

20. Overgrazing by the natives- A town of black-tailed prairie dog (Cynomys ludovicianus) on severely degraded High Plains range on which the climax (potential natural vegetation) was a needle-and-thread--dominated mixed prairie with blue grama, buffalograss, and Indian ricegrass as associates. This was the same range site, Loamy Plains, as that of the cattle-induced shortgrass disclimax and the undisturbed needle-and-thread mixed prairie described immediately above. Along this railroad right-of-way black-tailed prairie dogs had established their town resulting in much bare soil and plant cover primarily of plains pricklypear and with stiff greenthread, pale evening-primrose and/or scarlet globemallow supplying most of the herbaceous cover with relative proportions varying at microscale. All remaining blue grama (of which there was little) had been closely clipped so that the about the only remaining grass cover was that of buffalograss. There was not even much cover of cheatgrass which, along with buffalograss, was relatively abundant immediately below track bed of the railroad.

That needle-and-thread was the potential natural dominant (as on the exclosure--outside of the fence--shown above) was clearly shown by two plants of needle-and-thread in the middle of pricklypear patches where, of course, prairie dogs did not venture.

How "natural"--if natural at all--was a "dog town" on railroad tract exclosures? The answer was unknown to this author, but he hastened to point out that range plant communities along railroad rights-of-way have long been regarded as relict vegetation. Railroad corridors have served as relict areas or reference vegetation for decades. Railroad rights-of-way are about the only sources of native prairie left in much of the Corn-Soybean Belt. Abandoned tracks are now used as hiking trails, bridle paths, and "natural parks".

Anyway, prairie dogs had degraded this mixed prairie vegetation to a much lower seral stage (including.contributing to brush [pricklypear] invasion).

Weld County, Colorado. Mid-June (late vernal aspect). FRES No. 38 (Plains Grassland Ecosystem). Mixture of K-57 (Grama-Needlegrass-Wheatgrass) and K-58 (Grama-Buffalograss). SRM 608 (Wheatgrass-Grama-Needlegrass). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 
A smorgasbord of range plant communities- The section immediately below presented vegetation from four range sites (Loamy Plains, Shaley Plains, Clayey Plains, and Sandy Plains) that occurred within apporxomately a mile and a half radius of each other in northeastern Colorado. These photographic samples gave some indication of the remarkable diversity of grassland and grass-shrub savanna communities that developed in the Central Great (High) Plains. Grasslands are "boring" or "monotonous" only to uninformed, inexperienced, or disinterested traveler.
 

21. Mixed prairie mosaic- Two acrosss-the-land vistas of climax mixed prairie in the Central High Plains. This grassland had as its apparent potential natural vegetation a vegetational mosaic "put together" as intermixed intermediate-size areas of 1) blue grama-buffalograss shortgrass; 2) needle-and-thread-dominated midgrass; 3) western wheatgrass consociations; and 4) scattered plants of sand dropseed, red threeawn, needleleaf [caric] sedge (Carex duriuscula= C. eleocharis= C. stenophylla ssp. eleocharis), fringed sagebrush, scarlet globemallow, pale evening-primrose, stiff greenthread, wild alfalfa or slender scurfpea (Psoralea tenuifolia), and plains pricklypear, this latter being the sole shrub component of this vegetation. A tallgrass element was lacking from this mixed prairie this grassland being a midgrass-shortgrass prairie which--as was shown above and below--on certain range sites was readily degraded into a grazing shortgrass disturbance climax.

The first of thee two photographs featured an area of buffalograss-blue grama shortgrass turf with considerable cover of plains pricklyper. the second photograph local "spots" of shortgrass and wesstern wheatgrass colonies in foreground with stands of needle-and-thread, sand dropseed, and red threeawn in midground. Most common (and conspicuous at this season) forb was stiff greenthread. Both buffalograss and needle-and-thread were at peak anthesis while western wheatgrass spikes had just emerged from their boots. Blue grama was "a long-way off" from blooming and, in fact, had not in the main elongeted its shoots beyond mid-height of adult stature. More precisely, blue grama was not at adult stage in this vernal society. Thus blue grama was under-represented in the vernal aspect and in overall appearance. Conversely, needle-and-thread, a cool-season midgrass, was over-represented in these photographs; however, it would have under-represented while blue grama would have over-represented a month to six weeks later at peak of warm-growing season and estival aspect. Such is the nature of range plant communities that are "natural mixtures" of cool-season and warm-season species each group of which has species that are dominants and associates in their own season.

Time (seaonal progression) of phenological development was a major component or characteristic of mixed prairie vegetation in all of these photographs.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect). FRES No. 38 (Plains Grassland Ecosystem). Mixture of K-57 (Grama-Needlegrass-Wheatgrass) and K-58 (Grama-Buffalograss). SRM 608 (Wheatgrass-Grama-Needlegrass) and SRM 611 (Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

22. Integration of midgrasses and shortgrasses- "Photoquadrant" of range vegetation on a midgrass-shortgrass mixed prairie in Central Great (High) Plains. Species ranged from the midgrasses, western wheatgrass and needle-and-thread down to shortgrasses (mostly buffalograss and blue grama) plus needleleaf caric sedge and such forbs as fringed sage, stiff greenthread, pale evening-primrose along with a shrub component in plains pricklypear.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

23. Botanical quilt (or What makes a mixed praire) - More of the mixed prairie patchwork consisting of both midgrass and shortgrass species. In these two "phototransects" the dominant midgrass (and dominant vernal) species was needle-and-thread with sand dropseed the local associate midgrass. Both of these species were conspicuous in both photographs. The dominant shortgrass at this vernal stage of the annual cycle (ie. vernal aspect) and in this vernal society was buffalograss which was at peak anthesis. Blue grama was the local associate shortgrass though at other local habitats (microsite) blue grama was co-dominant. Blue grama would be predominant over buffalograss in the In the estival aspect and society by which time blue grama whould have attained adult growth of shoots. Conspicuous forbs were stiff greenthread (first photograph) and scarlet globemallow (second photograph). There were scattered plants of fringed sage and wild alfalfa or slender scurfpea. Plains pricklypear was so sparse as to be undectable in these photographs.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

24. Three cuurtain calls for the botanical cast- Three "photoquadrants" showing the range plant community with representative species of a midgrass-shortgrass mixed prairie in the Central Great (High) Plains at peak standing crop of the vernal society. The first of these three photographs showed the "fenceline-like" edge between a local midgrass community (dominated by needle-and-thread in this example) and a local shortgrass community (co-dominated by buffalograss and blue grama in this example). These local communiites could be regarded as herbaceous stands.

The second photograph was of a more composite community where shortgrass and midgrass stands overlapped as a local ecotone (transition zone at local scale). Range plant species in this second "photoquadrant" included blue grama, buffalograss, sand dropseed, red threeawn, western wheatgrass, needleleaf sedge, fringed sage(brush), scarlet globemallow, and plains pricklypear.

The third "photoquadrant" was still yet another local community which in this instance was a midgrass stand of needle-and-thread (primarily) and sand dropseed (secondarily) with plains pricklypear as a ground-level shrub. The pricklypear (along with pale evening-primrose) was in flower.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

25. Co-dominant shortgrasses- Ground-level views of the two dominant shortgrass species, blue grama and buffalograss, on a Loamy Plains range site in the Central Great (High) Plains in late vernal aspect and vernal society. Blue grama was on the left in the first slide and on the right in the second slide and vice versa for buffalograss.

Buffalograss was at its maximum vegetative and floral stages of phenological development (full-growth stage of annual shoot elongation [unless very fortunate amble moisture caused later growth] and peak anthesis) whereas the later-maturing blue grama had made a much lower proportion of its annual shoot growth/development at this point in the current growing season. On the Central Plains Experimental Range Dickinson and Dodd (1976) studied phenological development of major plant species and reported that time of flowring was frequently inconsistent with regards to warm- vs. cool-season species. For example, the warm-season buffalograss bloomed at roughly the same time as the cool-season western wheatgrass. Likewise, time of anthesis in cool-season species, needle-and-thread and bottlebrush squirreltail, could be closer to that of buffalograss than buffalograss was to the other warm-season dominant shortgrass, blue grama (Dickinson and Dodd, 1976, table 2). Unlike most other Bouteloua species blue grama is a long-day plant with regard to flowering (Olmsted, 1943). On the range shown here blue grama more commonly bloomed in late June to July (Dickinson and Dodd, 1976, table 2).

The major differences between these two erogrostoid dominants is in general habit with buffalograss being a sod-forming shortgrass with long stolons while blue grama is largely a bunchgrass (cespitose or tufted) that sometimes forms a relatively large matlike growth from short rhizomes (Hitchcock and Chase, 1951, ps. 540, 545; Gould, 1975, ps. 351; 355, Shaw, 2008, ps. 89, 99). Aboveground growth features of blue grama were reported in a classic paper from the Central Plains Experimental Range (Turner and Klipple, 1952). In this author's experience blue grama more frequently grew in this mat (semi-sodforming) form on this and surrounding ranges of the Central High Plains than on ranges in the Southern High Plains where it consistently grew in the more chatacteristic cespitose habit. The general rule is that blue grama is a bunchgrass whereas buffalograss is a sod-forming grass, but there is considerabale phenotypic plasticity so that blue grama has more of a semi-sodforming shortgrass in the Central and Northern Great Plains, especially under heavier grazing (Wynia, 2007).

In addition--or as a corollary--to general morphology or growth habit of these two shortgrass species there have been several general studies into their general biology or natural history as well as specific characteristics. One of the characteristics of range grasses that was once widely studied involvedd characterizations of height-weight relations often expressed as height:weight ratios, especially as related to utilization or degree of use (Cook et al., 1962, ps. 114-119). Cook et al. (1962, ps. 115, 118) reproduced two figures showing this relationship in blue grama (Figure 3) and blue grama and buffalograss (Figure 7). With light to moderate grazing threr is proportionately greater weight in seed stalks (sexual shoots) of blue grama than in buffalograss, Turner and Klipple (1952) found that contribution of sexual portions of tillers in blue grama varied by a factor of 2.5 (10-25% of aboveground biomass) in different years.

In general growth habit and and time of flowering the co-dominant shortgrasses, both warm-season species, complemented each other and timed their phenological development so as to minimize--to some degree--overlap in time and space thereby reducing interspecific competition.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

26. Expanse of shortgrass- Two landscape-scale scenes of blue grama-buffalograss shortgrass plains range. On the "tight land" of shallower soil, especially of the surface layer (Soil conservation Service, 1982) than that of range sites represented above (Loamy Plains range site) and below (Sandy Plains range site) the two co-dominant shortgrasses, buffalograss and blue grama, comprised a substantially greater proportion (cover, apparent biomass, general abundance) of the range plant community. That difference (proportionately more shortgrass than midgrass species) did not appear to be due wholly to range site. The range introduced here and described in several subsequent photographs appeared to be--at least in part-- a grazing disclimax were long-term heavy grazing had reduced relative cover and herbage of midgrass species and where there was much greater portions of annual forbs.

This conclusion was based not so much on lesser portions of needle-and-thread (a species whose favored habitat is sandier soil) or western wheatgrass that thrives best in lower-lying einvronments like swales, but in the much greater cover of plains pricklypear and, even more so, on cover and density of annual invaders, most notably woolly or bristle-bract plantain (Plantago patagonica) and common, dense-flower, or prairie pepperweed (Lepidium densiflorum). Woolly plantain is vriable in life span ranging from the typical annual through biennial to short-lived perennial (McGregor et al. (1986). Both of these are native species, but they have invariably been recognized as opportunistic species (eg. on waste grounds) and indicators of disturbanceare as for instance by McGregor et al. (1986) and Weber (1990). In addition, western wheatgrass, the major midgrass species on this range, had received much greater utilization than the two shortgrass dominants on the range that was being (and, in the past, had been) grazed rather heavily to a fairly uniform stubble height.

One of the most widely cited stocking rate papers ever published was that for blue grama range conducted on the Central Plains Experimental Range (Bement, 1969).

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Shaly Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

27. Shortgrass vegetation and a sample of its turf- Transect-scale scene of blue grama-buffalograss shortgrass plains grassland (first slide) and local or quadrant scale view of the sward of this shortgrass range (second slide) under current moderately heavy (stocking was between moderate and heavy rates). In the second photograph almost all of the standing crop was blue grama and buffalograss. The latter was at peak standing crop and full anthesis whereas blue grama had not commenced elongation of sexual shoots.

Physiogonomy and structure of this semiarid, plains grassland as shown in the first of these two slides and the two immediately preceding slides (especially the second) revealed that this range vegetation could be interpreted as a shrub-shortgrass savanna in which the proportionately high cover and density of plains pricklypear showed this low-growing woody plant to be an associate species. Western wheatgrass was overall the distant third abundant grass on this range. Given the relatively uniform height to which this range herbage had been grazed western wheatgrass, a midgrass species, had been defolited to a much greater degree of use than those of the two dominant shortgrasses. This was one of the major reasons why this author concluded that this grassland vegetation was--to some extent--a grazing disclimax and not solely the product of this shallow-soil "tightland" range site. Bottlebrush squirreltail was also conspicuous on this range at this time, but it was widely scattered and less abundant than western wheatgrass.

Forbs on this range varied from stiff greenthread, conspicuous in the vernal society, scarlet globemallow, fringed sage, denseflower pepperweed, woolly or bristle-bract plantain, and spreading fleabane (Erigeron divergens). These forb species were presented in the next two two-slide sets.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Shaly Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

28. Patches of retrogression- Two "photoquadrants" of a blue grama-buffalograss-dominate plains grassland (or, perhaps more descriptively, a shortgrass-shrub savanna) on a limely upland that was--in part--a grazing disclimax. In addition to the two shortgrass dominants and plains pricklypear (which resulted in a savanna or savanna-like physiogonomy/structure) there were a number of forbs, both annual and perennial, on this range. Forbs were the "center of attention" in these shots. The first photograph presented fringed sage, scarlet globemallow, and woolly plantain while the second slide showed wooly plantain, scarlet globemallow, and spreading fleabane along with the conspicuous though widely scattered bottlebrush squirreltail. Also in the second photograph (lower right foreground) was a cute specimen of green-flowered hedgehog cactus (Echinocereus viridiflorus).

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Shaly Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

29. Spots of annuals- Local spot grazing in a blue grama-buffalograss shortgrass range in the Central High Plains. These were two grazing-induced microhabitats site Even within a grazing disclimax there can be spot grazing resulting in even more range degradation (retrogression) at this microscale, microsites of severe overgrazing. The first of these two "photoquadrants" featured both denseflower or plains pepperweed and wooly or bristlebract plantain. This latter forb was the "star attraction" of the second "photoquadrant". Shoots of blue grama and buffalograss were also present in both photographs.

These species like several of the others on this shortgrass range were presented and described below. Relatively high density and foliar cover of these two invaders (not to mention plains pricklypear) was one of the major reasons why this range worker concluded that the vegetation existing on this range was partially a gracing disturbance climax and not simply an edaphic climax.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Shaly Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

30. Stockers on shortgrass- Steers on late-spring blue grama-buffalograss upland range at outer edge of a sacrific area around a water tank. The dominant range species were blue grama and buffalograss. Scarlet globemallow and kochia (Kochia scoparia) were the major forbs (in that order). Plains pricklypear was very limited, but there was considerably more cheatgrass than on adjoining ranges, including other shortgrasss prairie and savanna, mixed prairie, and needle-and-thread--fourwing saltbush savanna.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Shaly Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

31. Range site variant- Mixed prairie on a soil higher in clay along the bench of a local draw or drainage in the Central Great (High) Plains. Rangeland shown here was Clayey Plains range site in contrast to Loamy Plains, Limy Plains, and Sandy Plains sites presented elsewhere in this section. This was a more mesic habitat than the Loamy Plains and Limey Plains range sites. Dominant species were needle-and-thread on slopes and western wheatgrass on floor of draw. Blue grama and buffalograss were associate species. There was more bottlebrush squirreltail than on the other range sites. Fourwing saltbush (Atriplex canescens) was the dominant shrub that replaced plains pricklypear that was the major woody species on Loamy Plains and lImey Plains range sites. Forb species were most of the same as described--most notably fringed sage, stiff greenthread, and scarlet globemallow--with the additions of Rocky Mountain bee plant or pink cleome (Cleome serrulata) and Astragalus adsurgens var. robustior known variously as tufted, purple, prairie, or standing milkvetch. The annual invaders, dense-flowered pepperweed and woolly or bristle-bract plantain, were very limited and there was no kochia.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 Plains Grassland Ecosystem). K-58 (Grama-Buffalograss). SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Clayey Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 
Another study in role of grazing on range plant communities in the Central High Plains-The next two photograph-caption sets showed how long-term grazing by range cattle shifted mixed prairie to shortgrass vegetation in the semiarid zone.
 

32. Tufted midgrasses to sodforming shortgrasses- A fenceline contrast (first slide) and general view of a stocker range (second slide) on a High Plains mixed grass-fourwing saltbush savanna. Immediately outside this perimeter fence the relict grassland-savanna vegetation was needle-and-thread, Indian ricegrass, and western wheatgrass with lesser cover and biomass of blue grama and buffalograss whereas the range plant community grazed by stockers at moderate to fairly heavy stocking rates was overwhelmingly blue grama and buffalograss. Important specification: this was not a matter that under this degree of use (pasture-wide and ignoring varying utilization rates of different species) midgrasses like needle-and-thread, Inidan ricegrass, and western wheatgrass were grazed to a stubble height similar to that of blue grama and buffalograss. No, the three midgrass species were not just utilized to greater propotions; they were much less abundant and, in fact, locally absent from the stocker pasture. These taller bunchgrasses had been reduced in abundance and, in some local areas, grazed out.

Longterm grazing use at whatever the stocking rate(s) had been and currently was had converted this range vegetation from a mixed prairie-savanna of three midgrasses and two shortgrasses to a predominately two-species shortgrass community. Had this photograph been taken a month later aand after current peak standing crop of the three midgrass species and buffalograss and, instead, at peak standing crop of blue grama the relative cover and botanical composition would have been the same as at the time of this photograph. For that matter, the physiogonomy of both grazed and ungrazed portions would have been similar because differences in adult height of blue grama where protected (outside the fence) and that of more closely grazed blue grama on the range would still furnish the same contrast in height, and in mixture of cespitose and sodforming species (outside the fence) and predominately sod-forming habits of shortgrasses (on the grazed range). (Recall from above that at this more northern latitude, and in contrast to the Southern High Plains, blue grama produces more of a matlike growth habit, especially under heavier grazing.) At this time in the annual growth cycle of grasses four of the five major grass species were either at or approaching peak growth and development. There were four phenological stages present: 1) :immediate pre-bloom, western wheatgrass; 2) mid-bloom, Indian ricegrass; 3) peak anthesis, buffalograss; and 4) soft-dough grain stage, needle-and-thread.

Note the small size of closely browsed fourwing saltbush in right foreground of the second slide which was compared to fourwing saltbush plants growing on a more moderately grazed range presented in the next three photographs. This moderately grazed range was directly across a section line road which separated it from the range shown in these two photographs.

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-57 (Grama-Needlegrass-Wheatgrass) converted to K-58 (Grama-Buffalograss). SRM 608 (Wheatgrass-Grama-Needlegrass) converted to SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 

33. Mixed grass-fourwing saltbush savanna- A mixed prairie grassland composition of blue grama, buffalograss, needle-and-thread, Indian ricegrass, and western wheatgrass with cover and density of fourwing saltbush (along with the nearly always-present plains pricklypear) so as to constitute a midgrass-shortgrass-savanna in the semiarid Central High Plains. The range presented in these three photographs was straight across from--and the same range site as--the more heavily grazed range shown in the two immediately preceding photographs. These two pastures were on opposite sides of a section line road.

The two major shortgrass species, blue grama and buffalograss, were the obvious co-dominants on this as on the heavier grazed range across the road, but these two were much less predominant on this lighter grazed pasture. Said another way, range vegetation seen here did not have proportions of the three major midgrass species (needle-and-thread, Indian ricegrass, and western wheatgrass) that were as great as those in the strip of relict vegetation outside the fence (as shown in the preceding slide set), but proportions (relative cover and biomass) of these three were was much higher than in the more heavily grazed stocker range across the road.

Cover and biomass of the three midgrass species were glaringly greater next to and within interspaces among shrubs, especially the larger fourwing saltbush plants. The main forb was scarlet globemallow.

Finally, students should notice all the plants of fourwing saltbush were much larger on this range with lower degree of use than on the more heavily stocked range on opposite side of the road. (This was very pronounced even with three different camera-to-subject distances.)

Central Plains Experimental Range (Agricultural Research Service), Weld County, Colorado. Mid-June (late vernal aspect).FRES No. 38 (Plains Grassland Ecosystem). K-57 (Grama-Needlegrass-Wheatgrass) converted to K-58 (Grama-Buffalograss). SRM 608 (Wheatgrass-Grama-Needlegrass) converted to SRM 611(Blue Grama-Buffalograss). Brown et al. (1998, p. 40) description: Cold Temperate Grassland 142, Plains Grassland 142.1, Mixed "Short-Grass" Series 142.13. Loamy Plains range site. High Plains-Flat to Rolling Plains Ecoregion, 25d (Chapman et al., 2006).

 
Soem of the major range plant species present in the estival society of of the shortgrass ranges on the Central Plains Experimental Range were included in the following portion of this treatment.
 
34. The dominant- Blue grama (Bouteloua gracilis) was co-dominant (with buffalograss) on a shortgrass plains range that was to some extent a grazing disclimax.

Agricultural Research Service Central Plains Experimental Range, Weld County, Colorado.Mid-June (late spring), early bloom stage.

 

35. Not a purple cow, but purple milkvetch- Purple, prairie, tufted, rattle, or standing milkvetch (Astragalus adsurgens var. robustior), and there are probably several other common names out there just waiting to be milked. There are a "gazillion" Astragalus species on the Western Range. Weber (1990, ps 183-188) listed almost 40 species of Astragalus for the eastern slope of Colorado. This is one of the more common species. These plants were growing in a moist draw on a range that had received light livestock grazing, at least in the current growing season.

Agricultural Research Service Central Plains Experimental Range, Weld County, Colorado.Mid-June (late spring), full-bloom stage.

 

36. Purple standing on the short prairie- Inflorescence of purple, prairie, standing rattle, or tufted milkvetch. Agricultural Research Service Central Plains Experimental Range, Weld County, Colorado.Mid-June (late spring), early bloom stage.

 
 

37. Plain pepper- Common or prairie pepperweed (Lepidium densifolium) on grazing disclimax shortgrass plains range. This was one of the major forbs on the buffalograss-blue grama range described above. It was frequently the local dominant plant. This annual crucifer is one of the classic indicator species of overgrazing or other disturbances, and on a diverse array of range plant communities.

The short, rounded fruits of this species are of the fruit type known as silicles, cruicifer fruits that are relative short in comparison to their length.

Agricultural Research Service Central Plains Experimental Range, Weld County, Colorado. Mid-June, early fruit-ripening stage of phenology.

 

38. Plain plantain- Wooly plantain or wooly Indianwheat (Plantago patagonica) was the other major forb on the buffalograss-blue grama grazing disclimax range described above. This annual, like about all other Plantago species, is a weed, both economically and ecologically. Wooly plantain is an invader and an obvious indicator species of disturbance such as overgrazing. Cause of the denuded microsite seen here was known but to God, but it was a textbook example of this native, pioneer range plant successfully invading "new land" and, thereby, setting the stage for revegetation of the denuded spot via secondary plant succession.

Fortunately, most of this range that had obviously been subjected to overuse for "quite a spell", was not to the state of degradation (= stage of retrogression) as was this microhabitat. Still, and even without complete baring of the soil surface, there was more than enough grazing abuse for this unpalatable range forb to have a nice home along with its "extended family" (ie. a healthy population of P. patagonica). Wooly plantain was also successful in establishing itself over much of this range where existing vegetation was less drastically impacted. Wooly plantain is not restricted to overgrazed ranges. Abundant populations can also be found, when growing conditions have been favorable, on properly grazed ranges. However, wooly plantain is generally unpalatable and eaten by livestock mostly when little else is available. It is a classic invader in the model of Clements (1920) and Dykersterhuis (1949). Stubbendieck et al. (1992. p. 387) described wolly Indianwheat as being good forage for sheep for which it can be "a major forage species on lambing rnges".

This warm-season forb also "established" itself in the range plant literature earning spots in the old standby Range Plant Handbook (Forest Service, 1937, W150), the popular Pasture and Range Plants (Phillips Petroleum Company, 1963, 2003), Notes on Western Range Forbs (Hermann, 1966, p. 271), and by earning a place on the 200 species Master Plant List for the International Range Plant Identification Contest, North American Range Plants (Stubbendieck et al., 1992, ps. 386-387). Perhaps the main attribute for making such a "big hit" was the extremely wide distribution of this species that extends from some the Canadian Maritime provinces to British Columbia and south deep into the Republic of Mexico (see above references).

Agricultural Research Service Central Plains Experimental Range, Weld County, Colorado. Mid-June, peak-bloom stage of phenology.

 

39. Wooly range wheat- Shoots (first slide) and inflorescences (second slide) of wooly Indianwheat or wooly plantain on a shortgrass (buffalograss-blue grama) distirbance climax. range. This was on an upland and "tightland" (versus sandy) form of mixed prairie under extreme semiridity. The common name Indianwheat was supposedly derived from the Indian practice of gathering the ripe seeds as a food source. But then again, was there anything the Indians did not eat over much of their hardscramble habitat? Most livetock and wildlife do not eat it.

Agricultural Research Service Central Plains Experimental Range, Weld County, Colorado. Mid-June, peak-bloom stage of phenology.

 
40. Green thread and yellow spools- Stand of stiff greenthread (Thelosperma filifolium var intermedium) on a heavily grazed mixed prairie that was closer to a grazing disclimax shortgrass plains range. Central High Plains. Weld County, Colorado. Mid June (late spring), peak-bloom stage of phenology.
 

41. Flowering shoots of stiff greenthread- Heads on shoots of stiff greenthread growing on a heavily utilized range in the Central High Plains.
 

42. Spreading across shortgrass- Spreading fleabane (Erigeron divergens) on a grazing disclimax form of shortgrass plains. There are various Erigeron species native to the Great Plains and closely adjacent regions like the Colorado Piedmont and San Luis Valley. Two more of these are Engelmann's fleabane (Erigeron engelmannii) and tufted fleabane (Erigeron caespitosus), the latter of these was shown and described below while the former was included with species of the black greasewood scrub treated in the Miscellaneous Shrubland chapter of Range Types. All of these are occasional rather than dominant or even associate composite forbs. They do provide a good example of speciation.

Agricultural Research Service Central Plains Experimental Range, Weld County, Colorado.Mid-June (late spring).

 

43. Something besides white or yellow- "Almost all" composites have heads with white or yellow petals so the purple corollas of tansey aster or tanseyleaf aster (Aster tanacetifolius= Machaeranthera tanacetifolia) afforded a proverbial welcome departure here on the grazing disclimax of a shortgrass plains range. OK, its weedy little beggar, but what the heck. A little variety with the buffalograss can't hurt too much. Besides these floral folk were holding their own smack dab in the middle of a black-tailed prairie dog (Cynomys ludovicianus) town. That's worthy of picture in itself.

Weld County, Colorado. Mid-June (late spring).

 

44. Green with envy- Green-flowered hedgehog cactus (Echinocereus viridiflorus) in its sexual prime. This cute little specimen was growing on the more-or-less manmade (disclimax) shortgrass plains of the Central High Plains described above. Most of the grass surrounding this cactus was blue grama with buffalograss second.

Echinocereus species are in Cactaceae subfamily Ceroideae.

Agricultural Research Service Central Plains Experimental Range, Weld County, Colorado. Mid-June, peak-bloom phenological stage.

 

45. Rocky Mountain bee plant or pink cleome (Cleome serrulata)- This annual forb of the caper family (Capparaceae) was growing in a moist draw on the deeper soil of an upland range in the Central High Plains. Its neighbors included the milkvetch known by such adjectives as purple, prairie, tufted, rattle, or standing (shown above) as well as wild alfalfa or scurfpea, blue grama, buffalograss, needle-and-thread, red threeawn, and sand dropseed.

In addition to the many colorful flowers borne in racemes, the trifoliate leaves (three leaflets) make this range forb readily identifiable and prominent on the Great Plains landscape.

Agricultural Research Service Central Plains Experimental Range, Weld County, Colorado. Mid-June, peak-bloom phenological stage.

 

46. One that can be stuck in anywhere- Local stand of scarlet globemallow (Sphaeralcea coccinea). One of the most common and widely distributed forb on mixed prairie through shortgrass plains grasslands is this member of the Malvaceae, mallow family. This bunch was growing on a green needlegrass-dominated mixed prairie range featured below, but millions just like it grew over the rest of western mixed prairie ranges (ie. this shot could have been just about anyplace in the Great Plains). Hermann (1966, ps. 179-180) reported that scarlet globemallow has a biological range extending from Alberta to Texas and into the Central Lowlands province as far east as Iowa with palatability varying from tremendously from poor (or even none) to good. Oddly, this species was not included in either the Range Plant Handbook (Forest Service, 1937) nor Pasture & Range Plants (Philllips Petroleum Company, 1963, 2003). Yet, there are countless acres of Great Plains grassland on which scarlet globemallow is the--as in the singlularly most abundant--range forb.

Scarlet globemallow is on the Master Plant List (of 200 species) of the International Range Plant Identification Contest sponsored by the Society for Range Management and described in North American Range Plants (Stubbendieck et al., 1992).

Washington County, Colorado. Mid-June (late spring), full-bloom stage.

 
47. Scarlet globemallow- Apices of sexual shoots (first photograph; Washington County,Colorado) and close-up of flower (second photograph; Costillo County, Colorado) of one of the most common forbs of the mixed and shortgrass country.
 

48. Pale face on overgrazed mixed prairie- Pale or white evening-primrose (Oenothera albicaluis) growing beside scarlet globemallow (most leaves seen here). Both of these range forbs were growing on a black-tailed prairie dog town the ground of which had very few other species. Apparently prairie dogs do not care to eat (or even clip off) plants of these two species. O. albicaluiss is one of the more common evening-primroses on the Central Great Plains.

Weld County, Colorado. Mid-June, peak-bloom phenological stage.

 

49. Pale faces up close- Detailed views of inflorescneces of pale or white evening-primrose on a black-tailed prairie dog town in the Central Great Plains. Weld County, Colorado. Mid-June, peak-bloom phenological stage.
 
Some of the Major Range Plant Species on the Shortgrass Plains
 
50. Buffalograss- The quintessential shortgrass species in full bloom (staminate inflorescences)- Erath County, Texas, May.
 

51. Shooting up shoots- A plant of male buffalograss with numerous sexual shoots (staminate shoots in case of this male plant). This dioecious species reproduces both sexually and asexually, this latter mode mostly via stolons although rhizomes are produced infrequently. The clonal characteristic of buffalograss is pronounced with sizeable areas (often measured in hundreds of square yards) of the soil surface covered by a single plant. Adventituous rooting at nodes along stolons gives rise to many "daughter" or "sister" plants (modules, ramets, or clones) of the original parent or "mother" plant (the unique geontype). Each of these modules in turn gives rise vegetatively (asexually) to still more modules or clones (=modular or clonal plants) each of which can send up sexual shoots of the same same sex as the genotype (ie. many staminate or pistillate shoots per module) of each individual of this dioecious species.

Erarth County, Texas. May; anthesis.

 
52. Male buffalograss inflorescences- Buffalograss is regarded as being either monecious or dioecious. If the latter is the case then the specimen in this slide is a staminate plant, but either way the inflorescences are staminate. A stolon or runner was presented in the lower left foreground to illustrate asexual reproduction along with the sexual mode. Buffalograss is one of the best examples with which to illustrate the phenomenon of a clonal organism. Each of the nodes along the stolon can produce a new daughter plant thus making the older clonal unit the mother or parent plant. Tarleton State University Hunewell Ranch, Erath County, Texas. May.
 

53. Study of a buffalograss ramet (and of photographic light)- Paired photographs of a vegetatively reproduced unit (a ramet or clone) of a genetic individual (genotype) of buffalograss. This pair of photographs (one on left was in full-sun; one on the right was under overcast sky) presented certain features with more clarity in either full-light or some degree of shade. This paired comparison was study of lighting conditions for revealing photography as well as the primary objective of showing a dominant shortgrass species.

Erath County, Texas. October; anthesis.

 

54. Clonal unit of buffalograss- Sexual shoots fully emerged on one vegetative unit (a clone) of male buffalograss. Sexual and asexual reproduction were both presented in these two photographs. Buffalograss typically blooms in both mid-spring and mid-autumn, but it is opportunistic and reproduces sexually when growting conditions (especially soil moisture) permit. (Note the various months of blooming represented by various photographs in this section.)

Erath County, Texas. October; anthesis.

 

55. Staminate flower clusters of buffalograss- Views of male inflorescences of buffalograss that developed in late summer in response to the blessings of good rains that fell in late summer and with above average temperatures.

Tarleton State University College Farm, Erath County, Texas. September, late summer.

 

56. Bull buffalograss in rut- Anthesis in staminate flowers of buffalograss. Like most of the native grasses of the semiarid plains buffalograss has to be opportunistic, especially with regard to sexual reproduction. The male inflorescences presented here and in the preceding slides were blooming in late summer following recent rains.

Tarleton State University College Farm, Erath County, Texas. September, late summer.

 
57. Close-up view of staminate inflorescences of buffalograss- Male inflorescences of buffalograss have the typical raceme of members of the Chloridae tribe. Students should note the raceme shared by such members as the grama grasses, cordgrasses, windmillgrasses, crabgrasses, bermudagrass. Tarleton State University Hunewell Ranch, Erath County, Texas. May.
 
58. Buffalograss- An individual buffalograss plant with pistillate inflorescences (caryposes in soft dough stage). Erath County, Texas. May.
 

59. Buffalo gals in full-bloom- Sexual shoots of female buffalograss with exerted stigmas. Erath County, Texas. May, mid-spring.
 
60. Burrs of buffalograss- The one-flowered pistillate spikelets of buffalograss occur in groups of three up to six or seven each of which is surrounded by glumes that form an enclosing, hard, globular burr. Erath County, Texas. May.
 

61. Springing forth-Young spring stolons of buffalograss with typical coloration of early growth and arrangement of leaf axils on shoots.Stolons are aboveground intervaginal (piercing of leaf sheath) shoots. All intervaginal shoots, of which there are two types in grasses (rhizomes being the other), are horizontal. This is in contrast to intravaginal shoots (= tillers) that grow vertically and up through (rather than peircing) the leaf sheath.

Tarleton State University College Farm, Erath County, Texas. Late Apri; vigerous spring-growth (shoot elongation stage).

 

62. Surviving drought on the Great Plains- Several plants (or modules,clones of the same genetic individual) of buffalograss undergoing drought stress in early spring. It is usually assumed that nonwoody grasses (ie. all but bamboo) do not have aboveground perenniating parts; that is, all shoots are only annual organs that die at end of the annual growth cycle. This is mostly true, however some species like buffalograss have shoots that sometimes live for two or even three years with periodic bouts of dormancy. Drought and temperatures below the critical temperatue are two dormancy inducers.

The shoots (culms and leaves) of the buffalograss presented here had some parts that were apparently dead and others that were obviously alive. It provided a good example of the "Is it alive or dead?" state of this eragrostoid species. Clearly this is a survival adaptation for grass life on the plains. A dramatic lesson if life, especially for such a short plant.

Central Plains Experiment Station, Washington County, Colorado. Late June: drought-stressed.

 

63. "Cured on the vine"- A combination of small, fine leaves tht tend to retain the nutritive content, dry winters in the semiarid zone with limited moisture to leach out nutrients in plant tissues, and stolons that can live for more than one growing season (or year) result in dry, brown, and apparently "dead" (or nearly so) buffalograss shoots (stolons) that are remarkably nutritious and palatable in winter (or whenever dormant). This phenomenon of self-cured, dried herbage of remarkable high nutritive value on the Great Plains (even in winter) was recorded (with reliance on written correspondence) in one of the enduring classics of the Western Range livestock industry: Trans-Missouri Stock Raising The Pasture Lands of North America: Winter Grazing (Latham, 1871; reprinted with an introduction by J.C. Dykes, 1962, ps. 15-21, 78, 80,81, 86). A few excerpts included: "... the grasses cure on the ground without losing any of their nutriment..." (p. 18), "... subsisting upon the natural grasses of the country, in the winter as well as summer; no preparation of hay or other food is necessary" (p. 78), and "[t]he grasses are highly nutritious, cure on the ground, remain as permanent food during the entire winter..." (p.80).

Of course the Great Blizzard of 1886 ended the "no hay-era" when snow and ice covered the shortgrasses (made shorter still by overstocking) terminating in the great "die-ups", but that disaster bred out of ignorance, glib optimism, and greed did not negate the fact that when herbage of range grasses, like buffalograss, was available it retained its nutritional quality even in winter.

Las Animas County, Colorado. Late June: atypical stage of growth due to drought dormancy.

 
 

64. Blue grama- Bouteloua gracilis is viewed by many range scientists as the single most important range plant in North America from the standpoint of its wide geographic distribution, dominance of total land area, impact on range ecosystems within its range, and forage contribution to range animal diets. Quite likely the only other range plant to offer any opposition to this distinction would be little bluestem, depending on whether certain taxa are interpreted as separate species or varieties of little bluestem. Of course any of the tallgrass species have the deck stacked against them now that so much of the land in their former species ranges was claimed by the plow. That matter clarified, students should remember that this is a widely distributed species (from the Atlanic states and provinces to the southwestern deserts and the western side of the Rocky Mountains). Blue grama occurs on some sites of every major grassland except the Pacific bunchgrass prairie. While the Great Plains is the center of it's range blue grama is locally common even in the shade of tallgrass species as in this example where it grew on a big bluestem- dominated prairie in the Dissected Till Plains of the Central Lowlands. The Central Lowlands is the general physiographic province of the Prairie Plains region and it's grassland vegetation.

Homestead National Monument, Gage County, Nebraska. August.

 

65. "King Grass of the Mixed Prairie"- Blue grama is the unquestionable overall dominant and the single most important range plant species of the mixed (and perhaps of the shortgrass) prairie. This is so in particular for the unit of potential natural vegetation designated as "Grama-Buffalo Grass" (K-65 in Kuchler, 1964; K-58 in Kuchler, 1966) extending from the Southern High Plains of Texas, Oklahoma, New Mexico, Kansas, and Colorado through to the Central High Plains of northeastern Colordo and southeastern Wyoming. This is probably the single largest unit of climax grassland vegetation in the Great Plains province. It would be rivaled only by the "Grama-Needlegrass-Wheatgrass" unit to its north (K-64 in Kuchler, 1964; K-57 in Kuchler, 1966). another climax grassland community in which blue grama is a dominant.

It would be difficult indeed to exaggerate the extent, economic and ecological importance, and role of blue grama in North American grasslands, and the drama of human occupation of this vast region. The noble Indian tribes of the Great Plains with their existence intricately tied to the buffalo depended on blue grama, a mainstay of the buffalo ranges, for their 10,000 to 12,000 years of occupation.

Blue grama frequently (perhaps even typically) grows in association with other range plant species, but it also forms natural and extensive single-species stands. These almost exclusive populations of blue grama or range plant communities in which blue grama is the sole dominant constitute what Clements termed a consociation. In the classic Grassland of the Great Plains Weaver and Albertson (1956, 149-150, 253-254) described co-dominance and close affilitation of blue grama and buffalograss. When blue grama is co-dominant with buffalograss it is--contrary to popular opinion and perception--blue grama that is the more drought-tolerant species (Weaver and Albertson, 1956, ps 33, 104). Clearly, "... buffalo grass is less drought resistant than blue grama" and, also, "[B]lue grama is much more drought resistant than buffalo grass... (Weaver and Albertson, 1956, p.79, 133, respective quotes). The stoloniferous buffalograss did spread faster and more effectively than the cespitose blue grama in revcovering from the Great Drought of the 1930s from which the preceding experimental findings were derived.

Texas Tech University High Plains mixed prairie unit, Lubbock County, Texas. October; peak standing crop and anthesis stages of phenology.

 

66. Blue grama in early morning sun- An individual plant of blue grama at anthesis with early morning sunlight catching features of this bunchgrass just right. All blue grama shoots are tillers (upright, intravaginated) so this species is strictly cespitose. At end of an extremely wet growing season that extended from the preceding winter through until early autumn the blue grama plants featured in this section had a high proportion of their shoots progress to the sexual reproduction stage. This individual plant was at peak bloom-- and beauty.

Texas Tech University High Plains mixed prairie unit, Lubbock County, Texas. October; peak standing crop and anthesis stages of phenology.

 

67. A study in shoots- A single blue grama plant most of the shoots of which developed to the stage of sexual reproduction. A wet growing season preceded by a wet pre-growth (dormant) season were the major plant growing conditions responsible for such a high proportion of sexually reproductive shoots rather than the typical condition in which substantially fewer tillers progress to stages of inflorescence development and anthesis. Even under drier conditions, however, short-shoot grasses like blue grama have a higher percentage of their shoots that advance to flowering.

Texas Tech University High Plains mixed prairie unit, Lubbock County, Texas. October; peak standing crop and anthesis stages of phenology.

 

68. Racemes of blue grama- The inflorescence type in Bouteloua has traditionally been regarded as a raceme, but in more recent times it was often described as an inflorescence consistinf of "short, spicate branches" (Gould and Shaw, 1983, p. 298). The racemes of the Chondrosium section of Bouteloua the racemes (spicate branches of the inflorescence) have numerous pectinate (an adjective referring to packed, downward-oriented floral units like teeth on a comb) spikelets (Gould and Shaw, 1983, ps. 299, 380).

The anthers in these racemes were fully exerted and conspicuous.

Texas Tech University High Plains mixed prairie unit, Lubbock County, Texas. October; anthesis.

 
69. Blue grama in dormant stage- This is an example of dormant (and ungrazed) blue grama illustrating the "cured-on-the-vine forage" feature of this species. The specimen in this slide was at the extreme western edge of the Texas West Cross Timbers. Young County, Texas. April.
 

70. Racemes of blue grama- Even after a wet winter and almost midway into a Texas spring a few spikelets persisted on this blue grama raceme. Young County, Texas. April.

 
 
71. Hairy tridens (Tridens pilosa= Erineuron pilosum)- This shortgrass species is usually classified as an invader on most range sites. It is most common on overgrazed range or otherwise disturbed land (eg."go-back land") on tallgrass, mixed, and shortgrass (plains) prairies. Palo Duro Canyon State Park, Randall County, Texas. June.
 

72. Scarlet Globemallow (Sphaeralcea coccinea)- This member of the Malvaceae (mallow family) is often the most abundant forb in western portions of the mixed prairie and on into the shortgrass plains. There appears to be some dispute as to the forage value of this forb. It was described by the Society for Range Management Intercollegiate Range Identification Contest committee (Stubbendieck et al., 1982) as having but fair to almost no palatability, but in a later edition the committee (Stubbendieck et al.,1992) described it as excellent for native small ruminants. Hermann (1966) reported forage values ranging from poor or none to good. Observations by New Mexico workers on the blue grama ranges of the Ft. Stanton Experimental Ranch suggested that scarlet globemallow was quite palatable not only to forb-preferring animals like sheep and mule deer but also to cattle (specifically large stocker steers). Either (or any) way it is one of the more common forbs on plains and mesa grasslands.

Guadalupe County, New Mexico. June.

 

73. Curly mesquite (Hilaria belangeri)- Sward of curly mesquite. This is one of seven Hilaria species in North America, four of which are important range grasses. According to Gould (1951, p. 159) H. belangeri is the most palatable of these species, all of which are sod-forming (rhizomatous and/or stoloniferous). Curly mesquite has been the Hilaria species typically regarded by rangemen as a dominant of the "shortgrass country" (both shortgrass plains and overgrazed mixed prairie) and a species associated with such other shortgrass species as buffalograss and blue grama. Other vegetation specialists, particularly vegetation classifiers and mappers, in more recent works interpreted galleta (H. jamesii) as the dominant Hilaria on the Great Plains grasslands. For example, the Kuchler (1964, 1966) unit K-58 (Gramagrass-Buffalograss) did not list curly mesquite (Kuchler, 1964, p. 65). The Society for Range Management (Shiflet, 1994) did not even mention curly mesquite in descriptions of rangeland cover types SRM 705 (Blue Grama-Galleta) and SRM 715 (Grama-Buffalograss) of the Southern Great Plains Region. Dick-Peddie (1993, p. 104) gave galleta and not curly mesquite as the associate of the codominants, blue grama and buffalograss, of plains-mesa grassland. Curly mesquite does not grow in the central and northern Great Plains, but galleta occurs as far north as Wyoming so it is the Hilaria species sometimes found in rangeland cover type SRM 611 (Blue Grama-Buffalograss) of the Northern Great Plains Region.

In the experience of the current author omission of curly mesquite was somewhat erroneous, misleading to say the least. From his observations this author felt that Thomas (in Correll and Johnston, 1979, p. 11) was much "closer to the mark" when he listed curly mesquite immediately following buffalograss as a major increaser species on the Texas Rolling Red Plains portion of the Great Plains. Perhaps this was the reason why other (and more recent) authors did not list curly mesquite: it is an increaser and not a decreaser on most range sites (ie. it is not a climax species or a major species of the potential natural vegetation).

[By the way, this was still more evidence that SRM rangeland cover types typically resemble quite closely the climax or potential natural vegetation in spite of statements that explained SRM cover type "classification is based on existing vegetation" such that of these types "...most do not..." coincide with those of Kuchler (Shiflet, 1994, p. xi-xii). In fact the SRM rangeland cover types of the Great Plains province included essentiallly all of the Kuchler units of potential natural vegetation, and most of the other Great Plains rangeland cover types that did not correspond exactly with Kuchler units were smaller spatial subunits of these. One thing was certain: if qualifying statements given in Shiflet (1994, ps. xi-xii) were taken literally there would definitely have been far more reference to curly mesquite as well as a curly mesquite rangeland cover type. There are thousands of acres in the Texas Great Plains on which the dominant herbaceous species is curly mesquite, typically with honey mesquite as a scattered overstorey. This plains vegetation is a widespread form of depleted range: a seral stage on rangeland damaged by various combinations of former cultivation or "go-back land", severe overgrazing, oil and gas activity, and perhaps unique meteorological sequences of events or even climatic changes.]

The indespensible Pasture and Range Plants (Phillips Petroleum, 1963, p. 43) explained that curly mesquite had "increased and invaded ranges where better grasses were killed out by abusive grazing". Furthermore, curly mesquite is less palatable than buffalograss and blue grama and goes dormant earlier in drought all of which enable curly mesquite to survive "when better grasses die or thin out". While curly mesquite forms a dense sward such as the one shown here it's "forage production is very low when compared to the better grasses it replaced." (Phillips Petroleum Company, 1963, p. 43).

Regardless of successional status, forage value, soil cover, or usefulness as an indicator species, curly mesquite is-- for better or worse-- a nonclimax dominant on many ranges throughout much of southern Great Plains, a vast range region. In something of an overstatement when applied to the Rolling and High Plains Hitchcock and Chase (1950, p. 485) got the essence of the situation in regards curly mesquite: "Curly mesquite is the dominant 'short grass' of the Texas plains". (When the Rio Grande Plains are included this statement was "right on target".) Silveus (1933, p. 361) wrote that curly mesquite "is one of the most important grazing grasses on the Great Plains of Texas and New Mexico, extending into Mexico". Curly mesquite is commonly about the only perennial grass providing forage and soil protection over a large portion of Great Plains grasslands.

The examples in this section were from the Texas West Cross Timbers (Shally Hills range site) which is about the eastern limit of this species that is more typical of the semiarid zone. Erath County, Texas. Estival aspect in moderate drought,Late August.

 
74. Growth habit of curly mesquite- Typical appearance of curly mesquite plants. Parts of three stolons of curly mesquite (diagonally aligned from lower left to upper right). Erath County, Texas. Late August.
 
75. Typical curly mesquite plant- This unit of a curly mesquite clone showed the usual habit and leaf features of this shortgrass species. Erath County, Texas. Estival aspect, late August.
 

76. Crawling across the rocks- Asexual (= vegetative) reproduction and the clonal structure of curly mesquite was obvious in this specimen as it sent out stolons and daughter plants over this sandstone. Note also however sexual reproduction by production of grain: "seed stalk" (culm with the fascicle arrangement of spikelets) in right foreground.

Erath County, Texas. Estival aspect in moderate drought, late August.

 

77. Curly mesquite runner- This stolon of curly mesquite had four daughter plants developing at nodes of the shoot. Curly mesquite is a clonal organism in which the genetic individual (the plant of an individual genotype) is the genet (= ortet) and the new daughter or sister plants are ramets (= modules) of the genet. Essentially all perennial plants are clonal organisms, but the new clones (modules or rametas) are very obvious-- hence the concept of clonal organization readily understood-- in sod-forming shortgrass species like curly mesquite and buffalograss.

Stolons are extravaginal shoots. They are secondary shoots arising out of the parent shoot (itself a secondary shoot-- as distinguished from the primary shoot that originated from the embryo asexual generations previously). In extravaginal shoots (which also include rhizomes) the new secondary shoots pierce or come up through the sheath, an organ of invaginated tissue (hence these piercing shoots are extravaginated). Intravaginated shoots are those which grow upward inside of (rather than piercing) the sheath. Intravaginal shoots are labeled tillers. Grasses whose secondary shoots are intravaginated (ie. tillers) have a tufted or cespitose growth form and are called "bunchgrasses". This is in contrast to "sod-forming grasses" like curly mesquite. (Some grasses like Indiangrass and many of the bluestems have both tillers and extravaginal shoots, especially rhizomes.)

Stolons and rhizomes are more effective than tillers in invasion of new ground by the genet (genetic mother plant). Said another way, extravaginal shoots are more efficient propagules for populating a plant's "resource frontier".

Erath County, Texas (Western Cross Timbers), Texas. Late August.

 
78. Curly mesquite module- "Close-up" view of a daughter plant (ramet or module) developing along a runner (stolon) which is an offshoot of the oretet or genet (the "original" plant of the individual genotype).
 

79 Curly mesquite spikes- Various portions of curly mesquite inflorescences were displayed for today's lecture. The infloresecence of curly mesquite (all Hilaria species for that matter) is a spike, an unbranched flower cluster-- the inflorescence-- in which the spikelets are sessile--without a pedicel or not pedicellate-- on the rachis. The rachis of curly mesquite is one of the most distinctive of any species of North American grass. It forms a right angle zig-zag pattern known to rangemen as the "crankshaft rachis".

Hilaria spikelets are arranged in fascicles, clusters or bunches, each of which (and each spikelet within which) is sessile. There are characteristically three spikelets per fascicle (two lateral spikelets, both of which have several florets that are each staminate, and a single central spikelet which is one-flowered and perfect).

Inflorescences in the second photograph were in various stages of maturity, including one that was immature (green).

Erath County, Texas. Late August, and after recent rains.

 

 

80. Broadleaf milkweed (Asclepias latifolia)- This is one of the more than two dozen species of Asclepias growing on the prairie and plains grasslands of the continental interior. It is one of the more common milkweeds on the Great Plains grasslands. There is amazing variation in the morphological features and preferred habitats of Asclepias species. One of the most obvious differences among milkweed species is in their leaves. Kingsbury (1964, p. 267) used the two divisions of: 1) narrow-leaved milkweeds (having "linear or narrowly lanceolate leaves") and 2) broad-leaved milkweeds ((usually greater than 1.5 inches wide over "much of their length"). Broadleaf milkweed is the accepted or preferred common name for A. latifolia which should not be confused with the general category of "broad-leaved milkweeds". Broadleaf milkweed was listed by Burrows and Tyrl (2001, p. 126) as one of 16 Asclepias species that are "particularly important toxicologically". The "poisonous principle" (ie. the toxin) is a group of organic compounds known as cardenolides which manifest themselves within the gastrointestional tract as well as by bleeding in trachea, lungs and the heart surface (Burrows and Tyrl, 2001, ps. 131-135).

***Note to beginning range students: While livestock losses due to poisonous plants may not be one of the major sources of losses industrywide, the importance to indvidual stockmen can be (often is) staggering. Like damage inflicted by predators, poisonous plant losses capture the attention, imagination, anger, and political action of livestock producers. Range Management professionals who work closely with stock-raisers (eg. Agricultural Extension agents, federal range conservationists, and agro-chemical product salesmen) should thoroughly familarize themselves with the fundamentals of the poisonous range plant problem. In range areas having histories of livestock losses (this includes any number of syndromes of lowered animal performance in addition to outright animal death) the range practitioner should cultivate a sound professional relationship with a veterinarian knowledgable in the field of poisonous plants. The earliest Range Management textbooks (eg. Sampson, 1923) included extensive coverage of the poisonous range plants. Most of the Agricultural Experiment Stations in the Western Range states published bulletins on poisonous range plants early in the history of these organizations which, as mandated by the Morrill and Hatch Acts, kept a close eye out for practical problems impacting ranchmen and farmers. In the context of this aspect of Range Management it is important that those anticipating careers in or closely related to this field learn the poisonous plants in their area. Producers want names (common ones will suffice), and they have great respect for those who can correctly identify the plants causing the stock poisoning.

The milkweed flowers have a unique structure. The petals of the corolla occur beneath a corona that is comprised of five hoods each typically having a beak or crest. Surrounded by the five-part corona is the actual flower or sex organ portion made up of a five-stamen androecium and the compound pistil or gynoecium which adhere to each other. Together the adnated stamens and pistil form a resultant structure called a gynostegium.

Crowley County, Colorado. July.

Man has proved to be one of the most effective plant dispersal agents. For better or worse (often unintentionally for worse) this includes dispersal of diaspores of plants (including bacteria and fungi in the generic sense of plant) that naturalize to become weeds or pathogenic pests. Under certain cropping systems or in some operations certain of these noxious naturalized plants are of value in production agriculture. This is especially the case for Range Management due to the extensive and often opportunistic nature of this ecological-based husbandry. Two common alien weed species of the Chenopodaceae (goosefoot family) that grow on North American range and fall under a general heading of "usually a weed but often a beneficial plant" were included with Great Plains grasslands.

 

81. Russian thistle or tumbleweed, the "tumblin' tumbleweed" (Salsola kali tenuifolia= S. pestifer= S. tragus= S. iberica)- This plant is not, precisely speaking, a thistle nor is it the only tumbleweed, there being several plant species that blow across the land in a rolling motion following breakage of their basal stem. This species is, however, the tumbleweed unless otherwise specified. Russian thistle is the more commonly used name and the preferred common name. The usual story has it that Russian thistle was introduced into South Dakota from Eurasia in contaminated flaxseed and that after a few decades it had thoroughly naturalized across much of the Western Range (Forest Service, 1940, W. 165). This species is indeed a weed in field crop production, but when young and later when dead and dry (and moistened by frost, snow, etc.) Russian thistle is rated as fair or higher in palatability. Perhaps the greatest value of this tumble weed is reduction of soil erosion by its extensive cover on abandoned farmland ("old fields" in the ecological literature; "go-back land" among rangemen, farmers, stockmen), overgrazed ranges, and oil and gas fields. It also provides cover for smaller species of wildlife such as upland game birds.

Russian thistle may at times be toxic due to either oxalates or nitrate accumulation and when dry it can cause slight mechanical injury by its pointed leaves (see next slide), but overall it is a fairly desirable range forb, especially on severely disturbed lands.

Mitchell County, Texas. October

 
82. Leader of Russian thistle- This terminal portion of one branch (there are hundreds per plant) of tumbleweed was included to show the spiny leaves and fruits which are urticles (small fruits with the pericarp free from the single seed; often viewed as a bladdery fruit). This annual species is one of the most prolific plants on Earth. Russian thistle produces thousands of the tiny fruits per plant and when the plant breaks off upon dying and rolls across the land it spreads seeds at a phenomenal rate. Mitchell County, Texas. October.
 

83. Kochia or summercypress or belvedere (Kochia scoparia)- This is another annual Eurasian chenopod that thoroughly naturalized on the North American Great Plains. Like Russian thistle this development has generally been viewed as somewhat beneficial (perhaps even more so) especially in Range Management, and for the same reasons. The forage value of kochia is good for both livestock and wildlife though it can cause nitate poisoning and other toxicities. The same can be said for most field crops of course. Kochia also provides protection against erosion. Like Russian thistle kochia is a tumbleweed. Shortly after the annual plant dies it breaks near the ground surface and is blown over the land effeciently distributing the gametophytic generation to produce the sporophytic generation in the next growing season. The tumble weeds like kochia and Russian thistle are some of the best examples of wind dispersal (anemochory).

Occasionally kochia has been planted and grown as a forage crop. This was mostly in the Southern High Plains region where kochia was seeded as an annual agronomic crop and managed for high-quality pasture for cattle having high nutrient requirements (eg. developing replacement heifers, lactating beef cows). Sheep and deer also find kochia palatable, often highly palatable at immature phenological stages.

The field of kochia shown here was being grown for certified seed to be sold to commercial growers for pasture plantings. Erath County, Texas. May.

 

84. Shoots of kochia- Two views of kochia showing characteristic leaves, apical buds, and color patterns on stems. Grant County, Washington. June; pre-bloom stage.
 
85. More on kochia- Branching pattern and leaf detail on Kochia scoparia. The two plants shown here lacked the more common stem stripes of this species. While leaves of some kochia plants turn red with older age the light maroon stripping is more pronounced on younger portions of shoots. Okanogan County, Washington.June; pre-bloom stage.
 
86. Branches of kochia- Leaves and inflorescences of Kochia scoparia. Erath County, Texas. May
 

87. Why kochia is an effective colonizer- Mature fruit on branches of kochia. The fruits of kochia are utricles, a fruit type characterized as an indehiscent, bladderlike structure having one seed which is loosely enclosed within the fruit wall (Smith, 1977, ps. 66, 311). The utricle is a common fruit type in the goosefoot family (Chenopodiaceae). Even though the fruit of kochia is tiny (as shown by these two photographs taken with a mircrolense), the single dark seed inside the utricle is even smaller. Nonetheless, this is a very effective sexual propagule or germule as this exotic and naturalized species grows to relatively large size (especially for an annual forb) on range, field, and fencerow. More importantly in this context is the effeciency with which this opportunistic, weedy plant pioneers freshly denuded land. Abandoned cropland (old fields or go-back land), overgrazed ranges and pastures, even barnyards and seldom-used corrals are ideal habitat for this colonizing species.

Erath County, Texas. October.

 

88. Smooth yucca or small soapweed (Yucca glauca)- This is the common species of yucca on the central grasslands from the tallgrass and mixed prairies to the western edge of the shortgrass plains. The sweet flowers are a delicacy to cattle, so much so that presence of flower clusters and seed pods are a giveaway that a range was not grazed when the soapweed was in bloom.

Hamilton County, Texas. May.

 
89. Four-wing saltbush (Atriplex canescens)- This member of the Chenopodiaceae is a valuable and widely distributed browse plant that was a dominant shrub of such diverse range types as mixed prairie and plains and mesa grasslands, Chihuhuan and Great Basin Deserts. Ias seen here i is a dioecious species (a male plant at left and female plant at right). Weld County, Colorado. August.
 

90. A widespread and prickly character- A specimen of plains pricklypear (Opuntia polycantha) growing in the sward presented in preceding photographs of mixed (mostly mid- and shortgrass species) prairie grassland on the Staked Plains. This cactus grows throughout almost the entire latitudinal extent of the Great Plains from the southern most part of the Llano Estacado to the Canadian Prairie Provinces.

Plains pricklypear is of such short stature that all but the shortest grass species (eg. buffalograss) overtop it. As such almost any fire regard less of intensity, rate of spread, etc. will kill high proportions of this cactus.

Muleshoe National Wildlife Refuge, Bailey County, Texas. October.

 
91. Plains pricklypear (Opuntia polyacantha)- This is the most common cactus on the vast grasslands of the Great Plains. Its range extends from the Chihuhuan Desert north and west to the plains grasslands of Alberta to rank as one of the northernmost cactus species in North America (Benson, 1982, ps.111, 382-393). University of Lethbridge, Alberta.
 

92. Sprawlin' in the shortgrass- Plains pricklypear on a locally disturbed microsite on mixed prairie in the Piedmont Plains to the west of the Southern High Plains and east of the Front Range in southeast Colorado. This cactus was growing on a grassland of blue grama, buffalograss, sand dropseed, western wheatgrass, cheatgrass, and silver bluestem. This area was undergoing a relative severe drought and most of the perennial grasses were dormant except for a few stolons on buffalograss and isolated tillers of blue grama. Even plants of plains pricklypear were conspicuously drought-stressed (see next slide).

Las Animas County, Colorado. Late June.

 

93. Shriveled but still sexy- Two consectuively closer views of parts of the plains pricklypear introduced in the preceding photograph. The first of these two slides featured the extremely shriveled condition of cladophylls (the padlike shoots) of this cactus. This "wrinkled" appearance was due to water loss from the typically succulent, water-storing shoots, one of the most important water-conserving, survival adaptations of this xerophytic species. The extreme condition of water-depravation in this plant was striking.

In spite of this extreme state of water-stress the plains prickly was blooming. It was persistently carrying out sexual reproduction and exchanging gametes to propagate the genes, the funadmental cellular unit of natural selection. Details of sexual reproduction were preented in the second photograph. A ripening berry (the fruit of cactus) produced in the previous year was to the immediate of the newly opened cactus flower (ie. two years and two phenological stages of sexual reproduction were shown in this slide).

Las Animas County, Colorado. Late June.

 

94. Sex in two kingdoms- Two newly opened flowers on the plant of plains pricklypear that was introduced two captions above. This tough little xerophyte on a mixed prairie range was performing sexual reproduction even under drought-caused water stress so severe that cactus cladophylls were shriveled from water loss As if not to be outdone, two hymenopterans (of a species unknown to this author) were also engaged in sexual reproduction adorned in the simple beauty of a cactus flower. Both plant and animal species were "dutifully" passing on the genes of their respective races to their posterity and to the preservation of biodiversity, structure, and function of this range ecosystem.

Could there be anything in creation that bespeaks better the meaning of life? The Creator Himself must surely have paused to marvel and smile approval on one of the routine miracles in His creation. It also seemed likely that if Charles Darwin had passsed this way he would have penned a note of the survival fitness of these two manifestations of natural selection. Another brief episode on the great grasslands of the continental interior.

Las Animas County, Colorado. Late June.

 
 
95. Walkingstick cholla- This is but one of many species of Opuntia. It is widely distributed across the grasslands of the Great Plains where its aspect dominance gives a savanna-like appearance to a sea of short- and midgrasses. It is an example of a succulent and woody wild flower. Guadalupe County, New Mexico, July.
 

96. Shootfire, fruits on cholla shoots- The fruit of walkingstick cholla is borne at apex of the fleshy, cylindrical stems of this common (often defining) shrub on the Southern High Plains (Llano Estacado, meaning Staked Plains). In this species of Opuntia the cactus fruits occur in small groups (clusters) in contrast to singularly along shoot tips in pricklypear.

Noland County, Texas. March.

 

97. A single cholla fruit- One fruit of cholla cactus removed to present details. The cactus fruit is interpreted as a many-seeded berry (Smith, 1977, p. 104). The fruit of walkingstick cholla is armed with short spines and glochids, but these are punty affairs as compared for example to those of many of the pricklypears.

Noland County, Texas. March.

 

98. Contents of cholla fruit- A fruit of cholla catcus cut open revealing seeds. First photograph was interior of fruit immediately after being cut open (note thichness of the fleshy portion of fruit wall and moist membrane around seeds). Second photograph was interior of fruit 24 hours after cutting open (note shrinkage of fleshy portion of fruit wall and dried membrane surrounding seeds as compared with appearance immedately following opening as shown in first photograph).

Noland County, Texas. March.

 
99. Bush morning glory (Ipomoea leptophylla)- This perennial forb is one of the most characteristic and conspicuous wild flowers of the mixed prairie and shortgrass plains range types. Crowley County, Colorado, July.
 
100. The large woody roots of bush morning glory profide a textbook example that most biomass of grassland, desert, alpine, and tundra plants is in their root systems. These massive roots store reserves of water and energy (largely as carbohydrates) that enable these marvelously adapted plants to survive bitter winters, prolonged droughts, defoliation, etc. through dormancy and then to initiate new growth (or regrowth) when conditions become favorable. Crowley County, Colorado, July.
 
101. Winter-fat (Eurotia lanta)- This chenopodacious browse plant furnishes critical winter feed to all species of range ungulates, including horses (Sampson and Jesperson, 1963; Stubbendieck et al., 1992). Otero County, Colorado, July.
 
102. Broom snakeweed (Gutierrezia sarothrae)- This is one of the dominant half-shrubs of many areas of the Mixed Prairie and Short Grass Plains range types. With regard to  woodiness and perennial nature of its shoots it defies ready definition, but perhaps it is best described as suffruticose meaning that it has decidedly woody permanent stems which extend up some distance from ground level but which then remain herbaceous and die at end of each growing season.  Broom snakeweed is a native half-shrub that under certain conditions becomes a dreadful weed dominating millions of acres of range even ranges in Excellent condition. Mechanisms that trigger this invasion vary. This pest is not just the result of overgrazing, but it can drastically reduce yields of palatable forage. Then strangely after a number of years (and large sums of money spent on research and control) broom snakeweed disappears as suddenly as it appeared. The problem (and politics) of broom snakeweed caused a major research effort by the New Mexico Agricultural Experiment Station resulting in many publications. This is an example of the “pracitical education” at our grand land grant universities as established by the Morrill Act of 1862.  Hays County, Nebraska. October.
 
103. Inflorescences of broom snakeweed- Midland County Texas. October.
 

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