CHLORIDES 



217 



1 terminal, the other a short distance below, both nearly sessile 

 and more or less ascending, about an inch long, somewhat curved; 

 spikelets sessile, about 5 mm. long, densely crowded on one side of 

 the pubescent rachis; glumes narrow, the upper villous and more or 

 less beset with dark papillae, the lemma pubescent; rudiment 

 rounded, 3-awned. The end of the rachis does not project beyond 

 the spikelets. The spikes turn with the wind like vanes. In the 

 less arid portions of the Great Plains this species forms a rather 

 compact sod; in drier regions the tufts are isolated. This is some- 

 times called blue grama but to stockmen it is usually known merely 

 as grama. It is the most important economic species of the genus, 

 ranging on the Great Plains from Manitoba to South America and 

 westward into New Mexico, Arizona and southern California. 



Bouteloua hirsutu Lag. Black grama. Resembles the preceding 

 but differs in the prolongation of the rachis 

 as a naked point 5 to 8 mm. beyond the 

 spikelets, and in the more hairy second 

 glumes with prominent black papillae. The 

 range is about the same as that of the pre- 

 ceding but does not extend so far north. 



Bouteloua curtipendula (Michx.) Torr. 

 Tall or Side-oat grama. Culms 2 to 3 feet 

 high, the spikes numerous, 30 to 50, 

 arranged, by twisting of the peduncles, 

 along one side of the upper part of the 

 culm for 6 to 10 inches, about % inch 

 long, the spikelets appressed, 5 to 8 in 

 each spike. Prairies and plains, from 

 Ontario to Montana and south through 

 Mexico to South America. 



FIG. 48. Bulbilis dactyloides. Staminate plant, 

 ; spikelet, X4. 



