518 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



ment, broad, awnless or with a single awn, usually developed, o — 



Mesas and rocky hills, New Mexico, Arizona, and northern Mexico. 



12. Bouteloua rothrockii Vasey. Rothrock grama. (Fig. 1095.) 



Perennial, sometimes appearing to be annual; culms tufted, erect, 25 



Figure 1091.— Distribution of 

 Bouteloua simplex. 



Figure 1090.— Bouteloua simplex. Plant, X 1; 

 spikelet, X 5. (Griffiths 7362, Ariz.) 



Figure 1093.— Distribution of 

 Bouteloua barbata. 



Figure 1092.— Bouteloua barbata. Plant, X 1; 

 spikelet, X 5. (Griffiths 6095, Ariz.) 



to 50 cm tall; blades 2 to 3 mm wide; axis 10 to 25 cm long; spikes 4 

 to 12, 2.5 to 3 cm long, straight to subarcuate; spikelets 40 to 50, 

 about 5 mm long; fertile lemma pilose at base, deeply cleft, the awns 

 (1 to 2 mm long) spreading, the intermediate and lateral lobes fim- 

 briate; rudiment densely bearded at summit of rachilla joint, cleft 

 nearly to the base, the lobes broad and rounded, the awns mostly 

 exceeding those of the fertile lemma; a second rudiment, broad and 

 awnless, usually developed. % — Mesas, canyons, and rocky hills, 

 in open ground, or among brush, Arizona and southern California 

 (Jamacha), south to northern Mexico, 



