MANUAL OF THE GRASSES OF THE UNITED STATES 



515 



FIGURE 1084. Distribution of 

 Bouteloua curtipendula. 



rudiment with stout pubescent awns about 5 mm long, the long narrow 

 intermediate lobes glabrous; a second similar but smaller rudiment 

 usually developed. 21 Rocky hills, southern Arizona and Sonora, 

 Mexico. 



6. .Bouteloua chondrosioides (H.B.K.) Benth. (Fig. 1087.) 

 Perennial, tufted, leafy at base; culms erect, 20 to 50 cm tall; blades 

 2 to 3 mm wide; axis 4 to 6 cm long; spikes 4 to 



6, rhomboid-oblong, ascending, 1 to 2 cm long, 



the rachis densely pubescent, the tip 3-cleft; 



spikelets several, subpectinate ; rachis broad, 



densely pubescent on the margin; glumes and 



fertile lemma densely pubescent, the lemma 



3-cleft, the divisions awn-tipped; rudiment cleft 



nearly to the base, the middle awn broadly 



winged, the lateral ones slender, all spreading 



01 Mesas and rocky hills, western Texas, southern Arizona, and 



Mexico. 



7. Bouteloua radicosa (Fourn.) Griffiths. PURPLE GRAMA. (Fig. 

 1088.) Perennial, tufted, from a stout rhizomatous base; culms 



erect, 60 to 80 cm tall; blades 2 to 3 mm wide, 

 sparsely papillose-ciliate on the margin, mostly aggre- 

 gate toward the lower part of the culm, the upper 

 part naked; axis 10 to 15 cm long; spikes mostly 7 

 to 12, oblong, 2 to 3 cm long; spikelets mostly 8 to 

 glumes broader than in other species; fertile 

 lemma indurate down the center, with 3 

 awns, the middle longest^ and no inter- 

 mediate lobes; rudiment with 3 awns 5 to 

 8 mm long and no intermediate lobes, 

 usually containing a palea and staminate 

 flower, sometimes a perfect flower, the 

 lower floret being staminate. 01 Rocky 

 hills, southern New Mexico to southern 

 California and Mexico. 



8. Bouteloua filiformis (Fourn.) Griffiths. 

 SLENDER GRAMA. (Fig. 1089.) Resembling 

 B. radicosa', culms erect or geniculate-spread- 

 ing, sparingly branching, the base not 

 rhizomatous; spikes ascending to spreading, 

 mostly about 1.5 cm long, sometimes as 

 much as 2 cm; spikelets mostly 6 to 10, 

 very like those of B. radicosa. QJ. Rocky 

 hills, Texas to Arizona and Mexico. 



SECTION 2. CHONDROSIUM (Desv.) Benth. 



FIGURE 1085. Bouteloua rigidiseta. 

 Panicle, X 1; spikelet, lemma, and 

 florets, X 5. (Griffiths 6370, Tex.) 



Spikes persistent; spikelets crowded (looser in B. eriopoda), pectinate; 

 florets falling from the glumes. (Chondrosium Desv. based on 

 C. procumbens Durand (B. simplex).) 



9. Bouteloua simplex Lag. MAT GRAMA. (Fig. 1090.) Annual, 

 tufted, prostrate or ascending; foliage scant; blades 2 to 3 cm long, 

 about 1.5 mm wide; spike solitary, 1.5 to 2.5 cm long, strongly arcuate 

 at maturity; spikelets mostly 20 to 30, about 5 mm long; fertile lemma 



