FORAGE PLANTS 27 
or are protected by spines, are all more or less grazed by 
stock, especially sheep. If there is an abundance of forage 
the animals select the more palatable and nutritious spe- 
cies. In overstocked areas the animals are forced more 
and more to eat unpalatable or even poisonous species. 
On the prairies and plains of the western states, the 
grasses form the chief element of the forage. The most 
important single species probably is buffalo-grass (Par. 
245). This is the dominant species on the Great Plains 
from the Dakotas to Texas and from the Rocky Mountains 
to the 100th meridian and beyond. This region is collo- 
quially known as the “short-grass country,”’ to distinguish 
it from the prairie regions to the east, where tall grasses 
prevail. On the plains of Texas and northern Mexico, 
the buffalo-grass is gradually replaced by a species of 
similar habit, the curly mesquite (Par. 212). 
The grama-grasses in numerous species in the West 
and Southwest and on the table-land of Mexico form an 
important and nutritive constituent of the ranges. The 
most important of these is the blue grama, called in the 
Southwest merely grama, and on the plains grama-grass, 
extending from Manitoba to South America. Like buf- 
falo-grass it is a “short grass’ and is frequently confused 
with that species. The three grasses, buffalo-grass, curly 
mesquite and grama-grass, form a nutritious forage after 
they have been cured in the autumn by the dry climate 
of this region. Hence the range will support stock through- 
out the winter if the conditions are favorable. Fall or 
winter rains, or an early frost, decrease the value of the 
forage. 
Other especially important western grasses are the 
various species of Agropyron, Andropogon and Muhlen- 
bergia. Pine-grass is important in Oregon and Washing- 
