GRIFFITHS—THE GRAMA GRASSES. 845 
cutting for hay. In the main the nutritious and valuable herbage 
of the grama grasses consists of their basal leaves, and these grasses 
are consequently adapted mainly to grazing. 
In the main the perennial species very well withstand heavy grazing 
and the abuses incident to the open range method of handling stock. 
Indeed, there are few if any grasses that are superior to them in this 
regard. Bouteloua gracilis is the species of prime importance in the 
prairie region, and, together with B. chondrosioides, B. filiformis, B. 
radicosa, etc., is also important upon the higher lands farther south. 
No recorded experiences upon the behavior of these plants under crop- 
ping systems in the Southwest are known except the general observa- 
tion that too close grazing reduces the vitality of the plants, and, if 
long continued, kills them out entirely (P1. 68, A). Upon the northern 
prairies many observations have been made upon the behavior of the 
prairie grasses when cut for hay. The extent and degree of cropping 
have been much more definitely observed in the prairie region. In 
the Dakotas, Bouteloua gracilis withstands grazing very well, but if 
grazed closely for even one season it takes it two or three years to 
recover. It is the common experience that hay can not be cut on 
the upland prairies oftener than once every two years. In other 
words, the removal of the ground cover of one year’s growth, as close 
as the mower takes it, sets the plant back at least one year, while 
burning is still more detrimental. But this applies to the prairie 
grasses in general. 
ADAPTABILITY TO CULTIVATION. 
Many efforts have been made to cultivate the different species of 
Bouteloua, especially during the grass-garden period of experimenta- 
tion in this country, from about 1892 to 1900. 
The most promising of all the species for field cultivation is B. 
curtipendula (Pl. 69, A), not that it grows any more readily than 
the others, but on account of its size and habit. All the species re- 
spond readily to cultural treatment, but none of them have a good 
seed habit, a very important characteristic in an agricultural grass. 
The seed can not easily be even properly thrashed. All that can be 
done is to strip off the spikes, which separate readily from the panicle 
upon maturity. The whole spike has been invariably sown. In 
B. gracilis and allied forms the spikelets readily separate from the 
spikes, but even here it would be impracticable to attempt to secure 
clean seed. - 
EXPLANATION OF PLATE 68.—A. A region in which about half a dozen species of Bouteloua grow in pro- 
fusion whenever summer rains are seasonable, in spite of the fact that it is continuously closely grazed. 
B. Scene in the Santa Rita Mountains, Arizona. Bouteloua curtipendula and tall forms of B. hirsuta and 
B. radicosa predominate, mixed with species of Leptochloa, Andropogon, Heteropogon, Muhlenbergia 
and Panicum. 
EXPLANATION OF PLATE 69.—A, Bouteloua curtipendula. B. Bouteloua gracilis. Both growing at 
Walla Walla, Washington. Photographs by Leckenby. 
