GRASSLAND VEGETATION. 
Figure 36.—A good sod of grama grass and nigger wool, with occasional plants of June grass and 
western needle grass. (Short grass.) The prominent flowering plants are the wind flower, bitter root, 
mountain lily, and townsendia. This grassland is most important in Montana and along the western edge 
of the Great Plains. Over much of this area small grains are grown during normal and favorable years. 
Glendive, Mont. 
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Figure 38.—A close stand of wire grass. (Short grass.) The taller wire grass obscures the grama 
and buffalo grass which form the bulk of the sod. This grassland lies between the pure short grass on the 
west and the bluestem bunch-grass on the east. Hays, Kans. 
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Figure 37.—A pure, even cover of grama and buffalo grass interrupted uniformly by small patches of 
bare ground. (Short grass.) A pure short-grass cover indicates soil moistened only to a depth of 1 or 2 
feet. Akron, Colo. 
Figure 39.—A grama grass-western needle grass cover with conspicuous perennials, such as silvery 
psoralea and purple corn-flower. (Short grass.) This type is intermediate between the needle grass- 
slender wheat grass of the prairie and the grama grass of the plains. Mandan, N. Dak. 
plains grassland. Although many other plants occur 
in this association, typical areas, except during wet 
years, appear as a pure open sod. The annuals, in¬ 
cluding plains plantain ( Plantago pw'shii) , annual 
fescue ( Festuca octo flora) , pennyroyal ( Hedeoma his- 
pida) , and beggar’s tick ( Lappula occidentalis) , are 
short-lived and seldom more than an inch or two high, 
and the perennials are also, for the most part, low- 
growing plants. During exceptionally wet years weeds, 
such as horseweed ( Erigeron eanadense) and gum weed 
(■Grmdelia squarrosa ), and taller perennial grasses, 
such as western needle grass ( Stipa comata) and sand 
sporobolus ( Sporoholus cryptcmdrus) , develop a cover 
of taller plants. Within this area, especially in the 
north, the small grains do fairly well in medium or 
wet years, but fail in dry years. The sorghums and 
short-season corns also do fairly well. Fall wheat is 
grown in the northern and eastern portions. 
Farther east, where the rainfall is greater, or on 
lighter land, where moisture penetrates rapidly, tall 
plants become more abundant. These are chiefly wire- 
grass ( Aristida longiseta) and psoralea {Psoralea 
tenuiflora) , which indicate conditions somewhat more 
favorable for crop production than a pure even sod of 
short grass. Two types, modifications of this, and 
transitions to the prairie type, are the wire-grass and 
the wheat-grass types. The soapweed {Yucca glauca) 
is one of the most prominent plants on this type of 
grassland on the Staked Plains of Texas. 
Wire grass (fig. 38).—This type consists of a more or 
less open cover of grama and buffalo grass with a scat¬ 
tered growth of wire grass {Aristida longiseta) and 
many other deeper-rooted plants, such as psoralea 
{Psoralea tenuiflora) , bush morning-glory {Ipomoea 
leptophyTla) , etc. It forms a belt between the grama- 
buffalo grass of the plains grassland and the bunch 
grass of the prairie grassland, and is most extensive in 
Nebraska, Kansas, and Texas. During wet years the 
deeper-rooted plants thrive best, but during dry years 
they often fail to grow. Here the conditions for crop 
production are more favorable than on the pure grama- 
buffalo grassland. 
Western wheat grass (fig. 35).—This grassland is 
characterized by an even sod of grama and buffalo 
grasses and a scattered growth of western wheat grass 
{Agropyron smithii). During favorable years, when 
the wheat-grass fruits abundantly, prairie hay is cut 
from this type. It presents a more luxuriant appear¬ 
ance than pure short-grass and produces a heavier crop 
of forage. As a rule it contains fewer nongrasslike 
plants, and often occurs as a practically pure cover. 
This type is distributed over the unusually heavy 
gumbo soils derived from Fort Pierre shales in South 
Dakota, Nebraska, and Colorado (fig. 3), and occurs 
locally over a much wider range. Agriculturally land 
of this type does not differ greatly ‘from land of the 
grama-buffalo grass type. 
Grama-no extern needlegrass (fig. 39).—In western 
North Dakota and portions of South Dakota (fig. 3) 
grama {Bouteloua gracilis) , with an admixture of the 
taller-growing western needlegrass {Stipa comata ), 
constitutes a large percentage of the grass cover. The 
attending moisture conditions are more favorable than 
under pure grama, and the vegetation is much more 
varied in appearance. Needlegrass when in fruit is 
much more noticeable than grama, and the whole area 
at times looks somewhat like the needlegrass-slender 
wheat grass of Minnesota. This type is intermediate 
between the grama of the plains grassland and the 
needlegrass-slender wheat grass of the prairie grass¬ 
land. Many plants from both the short grass and the 
tall grass areas are found here. Purple cone-flower 
{Echinacea angustifolia) , silvery psorale {Psoralea 
argophylla) , and June grass {Koeleria cristata) are 
the most prominent plants, with the exception of the 
dominant grasses. Under cultivation land charac¬ 
terized by this type is more productive than any other 
short-grass type. 
MESQUITE GRASS (DESERT GRASSLAND). 
This grassland occurs in Texas, New Mexico, and 
Arizona and extends southward far into Mexico (fig. 3). 
It is characterized by a growth not conspicuously differ¬ 
ent (figs. 40 to 42) from the short grass of the plains. 
The growth period in this grassland does not begin in 
the spring as in the plains grassland, but as a result of 
summer rains in July or August, which start the 
drought-dormant perennial grasses into growth. The 
evaporation is excessive, the temperature high, and the 
annual rainfall low, ranging from 12 to 18 inches. 
The grass cover is usually even and more open than 
the short grass, and the soil-moisture supply is usually 
utilized soon after the rainfall. Growth is relatively 
rapid and the grasses soon become dry in places. In 
this condition they furnish excellent forage. On most 
of this land the conditions for dry farming are not as 
good as on the short-grass land. The dry, hot summer, 
with the growth period limited to the hotter months of 
July, August, and September, restricts dry-land pro¬ 
duction to the sorghums and similar warm-weather 
crops, and assures the almost certain failure of small 
grains. Areas of pure grassland are not great in ex¬ 
tent, and much of the surface is covered by scattered 
desert shrubs such as mesquite, creosote bush, yuccas, 
black brush, and cat’s claw. The Emory oak of the 
chaparral type {Qioercus emoryi) often occurs on the 
grassland, forming open savannas. 
