MANUAL OF THE GRASSES OF THE UNITED STATES 513 



spikes 35 to 50, 1 to 2 cm long, purplish, spreading or pendulous and 

 mostly twisted to one side of the slender axis, this 15 to 25 cm long; 

 spikelets 5 to 8, appressed or ascending, 6 to 10 mm long; fertile 

 lemma acute, mucronate; rudiment with 3 awns and subacute inter- 



FlGURE 1080. — Bouteloua aristidoides. 

 Panicle, X 1; spikelet, X 5 (Grif- 

 fiths 7308, Ariz.) 



Figure 1082. — Bouteloua uniflora, X 10. 

 (Type.) 



mediate lobes, often reduced and inconspicuous. %_ (Atheropogon 

 curtipendulus Fourn.) — Plains, prairies, and rocky hills, Maine and 

 Ontario to Montana, south to Maryland, Alabama, Texas, Arizona, 

 and southern California; South Carolina (introduced) (fig. 1084). 



4. Bouteloua rigidiseta (Steud.) Hitchc. 

 (Fig. 1085.) Perennial, tufted, leafy at base; 

 culms erect, 20 to 30 cm tall; blades narrow, 

 flat or somewhat involute, 1 to 1.5 mm wide, 

 sparingly papillose-pilose; spikes 6 to 8, trian- 

 gular-cuneate, spreading, about 1 to 1.2 cm 

 long including the awns; spikelets mostly 2 to 

 4, crowded, ascending; glumes pubescent; fer- 

 tile lemma with 3 spreading awns, the inter- 

 mediate lobes acute; rudiment with stout spreading awns, much ex- 

 ceeding those of the fertile lemma, the intermediate lobes firm, pointed, 

 a second similar but smaller rudiment commonly developed. 01 (B. 

 texana S. Wats.; Polyodon texanus Nash.) — Plains and rocky hills, 

 Oklahoma, Texas, and northern Mexico. 



5. Bouteloua eludens Griffiths. (Fig. 1086.) Perennial, densely 

 tufted, leafy at base; culms erect, 25 to 60 cm tall; blades mostly 



Figure 1081.— Distribution of 

 Bouteloua aristidoides. 



