MANUAL OF THE GRASSES OF THE UNITED STATES 445 



scabrous twisted column, the total length to the bend 10 to 17 mm; 

 central awn divergent, 5 to 10 mm long, the lateral awns from obso- 

 lete to as much as 1 mm long, erect. % 



Figure 942.— Distribution of 

 Aristida orcuttiana. 



— Kocky hills and plains, Texas to south- 

 ern California (San Diego), and northwest 

 Mexico (fig. 942). 



Section 3. Chaetaria (Beauv.) Trin. 



Lateral awns more than 1 mm long, 

 usually well developed ; lemma not arti- 

 culate with the column of the awns. 

 8. Aristida basiramea Engelm. (Fig. 

 943.) Annual; branching at base, 30 to 

 50 cm tall; blades flat, as much as 15 cm 

 long and 1.5 mm wide; panicles terminal and axillary, the terminal 

 5 to 10 cm long, the axillary mostly enclosed in the sheaths; glumes 

 somewhat unequal, 12 to 15 mm long; lemma about 1 cm long; cen- 

 tral awn coiled at base, 10 to 15 mm 

 long, the lateral awns half to two-thirds 

 as long, somewhat spreading, o — Open 

 barren or sandy soil, Michigan and North 

 Dakota to Illinois and Kansas; intro- 

 duced in Maine (fig. 944). 



9. Aristida dichotoma Michx. (Fig. 

 945.) Annual; culms branched at base, 



Figure 943.— Aristida basiramea, X 1. 

 (Pammel 174, Iowa.) 



Figure 944.— Distribution of 

 Aristida basiramea. 



20 to 40 cm tall; blades short, the lower 

 mostly flat, scarcely 1 mm wide, the upper 

 involute ; panicles terminal and axillary, 

 the terminal usually less than 10 cm long, 

 the lateral small; glumes about equal, 6 

 to 8 mm long; lemma 5 to 6 mm long; 

 central awn spirally coiled, horizontally 

 bent, 3 to 6 mm long, the lateral awns 

 erect, about 1 mm long. G —Dry open ground, Maine to eastern 

 Kansas, south to Florida and Texas (fig. 946). 



10. Aristida curtissii (A. Gray) Nash. (Fig. 947.) Annual; simi- 

 lar to A. dichotoma, differing in the less branching habit, the longer 



Figure 945. — Aristida dichotoma, X 1 

 (Jackson 1S29, Del.) 



