Apr. 12,1924 Vegetation in the Semiarid Portion of the United States 105 
grass, being highly palatable to all livestock. Carrying capacity ranges from 15 
to 30 head of cattle per section, and in very favorable years, it makes sufficient 
growth on very favorable habitats to be cut for hay. 
(28) Hairy Grama ( Bouteloua hirsuta (Lag,)), Grama, and Sand Sage 
(Artemisia filifolia Torr.).—This type grows on sandy soils throughout the central 
Great Plains region, especially eastern Colorado, and is made up of an open 
stand of sand sage growing over an even sod composed mainly of hairy grama 
and grama. It has doubtful agricultural value except for sorghum and corn, 
since the soil is likely to blow if cultivated. As grazing land it will carry from 15 
to 25 head of cattle per section. It will not stand heavy grazing owing to the 
loose texture of the soil. The sand sage also comes in as a result of overgrazing 
which decreases the grazing capacity of the range. 
(29) Bunchgrass {Andropogon scoparius Michx.).—Lands on which an 
open stand of bunchgrass comprises most of the vegetation are classified 
under this type. It occurs on the sandhills and rough, rocky, or gravelly hills 
of the central or western high plains. It should not be confused with the rela¬ 
tively pure close stands of this grass on the loam soils of the eastern and southern 
high plains. The best type of this land is good corn or sorghum land, but in the 
western portion it often characterizes nonagricultural land. Bunchgrass when 
young is very palatable and nutritious to livestock and is also valued as winter; 
range since it is not so easily covered with snow as the short grasses. 
(30) Sand Hills Mixed. —Plate 4, B, illustrates a typical sand hills mixed 
type which consists of a mixture or alternation of sand sage, bunchgrass, big 
blue stem {Andropogon furcatus Muhl. or Andropogon hallii Hack.), sand- 
grass ( Calamovilfa longifolia (Hook.) Scribn.), hairy grama {Bouteloua hirsuta 
Lag.), and frequently a number of flowering plants. It occurs on sand hills 
or rolling sandy land throughout the central and southern Great Plains, but is 
probably most common in the sand hills of eastern Colorado. Thisttype of range 
supplies considerable forage and is especially valuable in dry years when little 
feed is produced on the hard lands. Its carrying capacity is from 20 to 50 head 
of cattle per section. As agricultural land it is subject to blowing and the whole 
area may be transformed by breaking into a blowout. ! 
(31) Black Grama and Wire Needlegkass.— Lands having a uniform sod of 
black grama with varying quantities of wire needlegrass are listed under this type. 
The amount of wire needlegrass present in this type is usually governed by soil 
conditions, this species being more abundant on lands having coarse gravelly soils. 
A verycommon type in southwestern New Mexico and eastern Arizona, growing on 
slightly gravelly, rocky, or sandy loam soils. Areas producing this type can be 
used for growing forage crops only in favorable seasons. Black grama is excellent > 
forage, but wire needlegrass is grazed only for a short time after growth starts. 
The carrying capacity of the black grama and wire needlegrass type ranges from 
15 to 30 head of cattle per section. 
<32) Black Grama and Iobosa {Hilaria mutica (Buckl.) Benth.).—This type 
is made up of varying quantities of tobosa grass growing in a relatively even 
stand of grass composed mainly of black grama. It usually grows in rather fine 
compact soils on flats that receive some flood water. The amount of tobosa 
grass in this type is directly proportionate to the amount of flood water received. 
This vegetative type occupies quite a large acreage in southwestern New Mexico 
and southeastern Arizona and possesses a farming and grazing value similar to 
Type (31). 
(33) Tobosa Grass. —The tobosa grass type is applied to vegetative associa¬ 
tions that are composed almost entirely of tobosa grass. This is the predominant 
type on flats and swales in New Mexico and eastern Arizona that are subject to 
flooding, where the soil is a fine compact loam or a clay loam. It occupies land 
