MANUAL OF THE GRASSES OF THE UNITED STATES 



Annual, resembling B. rothrockii; 

 culms erect or geniculate-spreading, 

 sometimes branching; blades papil- 

 lose-pilose; spikes 4 to 8, often flexu- 

 ous, commonly grayish purple, 2 to 

 3.5 cm. long; rachis papillose-pilose; 

 spikelets 40 to 65, about 6 mm. long; 

 second glume awned from a bifid tip, 

 the keel papillose-pilose with spread- 

 ing hairs ; fertile lemma densely pilose, 

 deeply cleft, the awns spreading, the 

 oblong intermediate lobes fimbriate; 

 rudiment densely bearded at summit 

 of rachilla, cleft nearly to the base, 

 the lobes obovate, fimbriate, the awns 

 exceeding those of the fertile lemma; 

 a second rudiment, broad, awnless or 

 with a single awn, usually developed. 

 O — Mesas and rocky hills, New 

 Mexico, Arizona, and northern Mex- 

 ico. 



12. Boutcloua rothrockii Vasey. 

 Rothrock grama. (Fig. 783.) Peren- 

 nial, sometimes appearing to be an- 

 nual; culms tufted, erect, 25 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; 



539 



Figure 783. — Bouteloua rothrockii. Panicle, X 1; 

 spikelet, X 4. (Griffiths 7185, Ariz.) 



Figure 782. — Bouteloua parryi. Panicle, X 1; spike- 

 let, X 5. (Griffiths 7277, Ariz.) 



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 lat- 

 eral lobes fimbriate ; 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 awn- 

 less, usually developed. % 

 Mesas, canyons, and rocky hills, in 

 open ground, or among brush, Ari- 

 zona and southern California (Ja- 

 macha), to northern Mexico. 



13. Bouteloua glandulosa (Cer- 

 vant.) Swallen. (Fig. 784.) Similar 

 to B. hirsuta; lower part of the 

 culms and the lower sheaths con- 

 spicuously papillose-hirsute with as- 

 cending or spreading hairs; blades 

 flat, attenuate, 2 to 3 mm. wide, 

 more or less ciliate or hairy toward 

 the base; spikes 1 to 3, ascending to 

 reflexed, the rachis prolonged beyond 

 the spikelets as a prominent bristle, 



