Apr. 12,1924 Vegetation in the Semiarid Portion of the United States 107 
favorable possibilities for grain production. It affords very good grazing, 
especially for cattle and horses, and has a carrying capacity ranging from 25 to 
60 head of cattle per section. 
(40) Curly Bunchgrass ( Festuca ovina L.).—Curly bunchgrass is a very 
common type on rolling foothills of eastern Idaho, western Colorado, and northern 
Utah, growing in deep rather coarse loam soil. It is frequently associated with 
Junegrass (Koeleria cristata (L.) Pers.), blue grasses (Poa), and Stipa. It 
frequently merges into the sage-brush type, where it is the dominant herbaceous 
species. The moisture requirements of this type are such that the lands it 
occupies can be successfully used for the production of wheat and oats, the main 
limitation being the length of growing season, which is frequently too short to 
mature grains. It affords excellent grazing, especially for cattle and horses, 
having a carrying capacity of from 30 to 60 head of cattle per section. 
(41) Mixed Mountain Grass. —A mixed stand of grasses composed mainly 
of bluegrass (Poa), curly bunchgrass, Junegrass, wheat bunchgrass, and needle- 
grass (Stipa), make up this type. About one-third of the stand of vegetation 
may also be composed of weeds, principally wild geranium ( Geranium incisum 
Nutt.), alum root (Sieversia ciliaia (Pursh) G. Don.), balsam root ( Balsamor - 
rhiza sagittata (Pursh) Nutt.), lupines, sunflower (Helianthella species), and 
Senecios. This type is common on rolling foothills and lower mountain lands of 
Colorado, Utah, and Idaho, usually occupying well-drained deep loam soils. 
The growing season is usually too short to mature cultivated crops, but this type 
furnishes excellent grazing, having a carrying capacity that ranges from 50 to 
100 head of cattle per section for a four to five months grazing season. 
( 42 ) Arizona Fescue ( Festuca arizonica Vasey).—Grass lands where 
Festuca arizonica is the predominant species are classified in this type. Its range 
is confined to foothill and mountain areas above 6,000 feet in Arizona and New 
Mexico, It is the most comon mountain bunchgrass in the Southwest, and is* 
frequently the predominant herbaceous species in open stands of yellow pine- 
timber. As agricultural land it is capable of crop production without irrigation 
during exceptionally good years. The growth season is best adapted to small 
grains. It affords excellent forage during its early season of growth, but on 
maturity it becomes too coarse to be grazed. It has a carrying capacity which- 
ranges from 20 to 30 head of stock per section. 
(43) Short-Lived Grass Type. —This type consists of a mixture of small 
short-lived grasses. The following are often prominent: Scleropogon brevifolius- 
Phil., Aristida bromoides H. B. K., Bouteloua aristoides (H. B. K.) Griseb., and 
short-season annuals. It is widely distributed in the Southwest, growing on 
mesas and foothills where desert or semidesert conditions prevail in a loamy soil r 
sometimes slightly sandy. This type usually marks badly overgrazed areas and 
is not therefore indicative of the character of the soil or potential grazing value. 
(44) Giant Wild-rye {Elymus condensatus Presl).—This species, illustrated 
in Plate 6, A, grows in a deep rich alluvial soil free of harmful quantities of alkali. 
It is also common in waste places, such as along ditch banks. It is widely dis¬ 
tributed throughout the Northwestern States, found usually in small patches 
and in isolated bunches, and is very conspicuous due to its tall bunchy growth, 
but the area it occupies is rather small. It marks land unusually valuable when 
placed under irrigation and is of very little grazing value owing to its coarse texture. 
(45) Weed Grass. —This type is limited chiefly to California where it is the 
principal type on the valley floors and lower foothills on lands containing little 
or no alkali. It consists of a more or less even stand of annuals or short-lived 
grasses, chief among which are three species of brome grass (Bromus species), 
wild oats ( Avenafatua L.), and filare, also known as alfilaria, ( Erodium cicutarium 
(L.) L’H6r.). In Washington and Oregon a similar type occurs on overgrazed 
