Apr. 12,1924 Vegetation in the Semiatnd Portion of the United States 103 
in western South Dakota, eastern Wyoming, and western Nebraska, are vege¬ 
tated by this type. It consists of a sod of grama grass and buffalo grass and 
varying amounts of wheatgrass. In dry years the short grasses are more 
abundant, but in wet years the wheatgrass appears to be the dominant species. 
Considerable native hay is cut from lands containing this type. It also fur¬ 
nishes a large amount of grazing for range stock. The carrying capacity varies 
from 30 to 75 head of stock per section. The heavy soil makes crop production 
doubtful during dry years, but relatively heavy during years of excessive rainfall. 
(17) Grama-Buffalo, and Wild Alfalfa. —The vegetation of this type is 
composed of an even sod of grama grass and buffalo grass over which plants 
of wild alfalfa are more or less equally scattered. The soil is similar to Type (9). 
This type does not occur to any appreciable extent north of Yellowstone River 
in Montana or in North Dakota. It indicates more than usual water supply, 
due either to precipitation or to flood water. The soil is 'deep as compared 
with Type (13), and it will often produce crops when the pure short grass land 
fails. The carrying capacity on most of the lands producing this type ranges 
from 30 to 65 head of cattle per section. 
(18) Grama-Buffalo Grass, and So apweed Yucca (Yucca glauca Nutt.).— 
The vegetative covering of this type is composed of an even stand of grama-buffalo, 
the latter usually predominating, with scattering bunches of soap weed yucca. It is 
very common in the southern Great Plains, growing on a loose, sandy loam soil. 
Land producing this type of vegetation is successfully used for growing corn 
and grain sorghums, and in some of the more favorable localities good yields of 
wheat are obtained in years of more than average precipitation. It provides 
nutritious and palatable forage, having a grazing capacity of 25 to 50 head of 
cattle per square mile. 
(19) Grama-Buffalo, and Mesquite (Prosopis glandulosa Torr.).—This is a 
very common type in the southern Great Plains of western Texas and eastern 
New Mexico, growing on hard lands. It is composed of an open sod of grama 
grass and buffalo grass, over which are scattering bunches of mesquite. Rainfall 
varies from 15 to 18 inches over the region occupied by this type. Moisture is 
insufficient, except in years of abnormal rainfall, to produce any cultivated crops 
other than sorghums. This type has a carrying capacity of 40 to 60 head of 
cattle per section. 
(20) Grama-Buffalo Grass, and Matchweed. —Plate 4, A, shows this 
type, which is made up of a sod of grama grass and buffalo grass over which is 
scattered matchweed in varying densities. The distribution is the same as 
Type (13). Where it occurs naturally it indicates land of doubtful agricultural 
value and grazing land of low carrying capacity, varying from 15 to 25 head of 
cattle per square mile. This type develops on land previously characterized by 
Type (13) as a result of overgrazing or breaking. - 
(21) Wheatgrass. —This grass usually does not form a sod, but is found in 
open stands consisting of upright single plants scattered uniformly over the 
surface. It is widely distributed throughout the western United States, growing 
in heavy clay soils that usually contain alkali. It is very common in southeast¬ 
ern Montana and northwestern South Dakota, and it is of doubtful agricultural 
value, due mainly to the heavy soils in which it grows. In years of abnormal 
precipitation, however, high yields of grain have been obtained on lands produc¬ 
ing this type. It is very palatable and nutritious to all classes of livestock, but 
because of the open stand and tendency to fail during dry years its carry nig 
capacity ranges as low as 10 head of cattle per section. The better areas will 
support 50 head per square mile. 
(22) Wire N eedlegrass. —In addition to wire needlegrass, this type frequently 
contains patches of short grass and a scattering of flowering plants. It is a common 
