346 MISC. PUBLICATION 243, U.S. DEPT. OF AGRICULTURE 
Annual, branched at base, erect or geniculate-spreading; culms 
scabrous or the lower part smooth, 50 to 100 cm tall; sheaths com- 
pressed-keeled, scabrous at least toward the summit, sometimes 
appressed-pilose; blades flat, scabrous, usually 15 to 25 em long and 
3 to 5mm wide; panicles cylindric, densely flowered, usually 3 to 5 cm 
long, the axis densely hispid-scabrous and also rather densely villous; 
spikelets about 2 mm long, the bristles about 5 to 6 mm long; fertile 
lemma coarsely transversely rugose (fig. 316). 
Sandy woods, southeastern United States; Cuba. 
Cusa: La Grifa, Wright in 1865. Laguna Santa Barbara, Ekman 
18118. Isla de Pinos, Britton and Wilson 14817. 
Ve L 
Zz 
FIGURE 316.—Setaria corrugata, X 1 (Pollard FIGURE 317.—Setaria macrostachva, X 1 
and Collins 253). (Hitchcock 13605). 
14. Setaria macrostachya H. B. K., Nov. Gen. et Sp. 1: 110. 1815. 
Mexico. PRAIRIE BRISTLEGRASS, 
Chaetochloa macrostachya Scribn. and Merr., U. S. Dept. Agr., Div. 
Agrost. Bull. 21: 29. f. 16. 1900. 
Perennial, tufted, usually pale or glaucous; culms erect or geniculate 
at base, scabrous below the panicle, 40 to 120 cm tall; sheaths more or 
less compressed-keeled; blades flat or folded, 15 to 40 em long, 3 to 
5 mm wide; panicles erect, spikelike, mostly 5 to 10 cm long, shghtly 
tapering above but not attenuate, densely flowered, or somewhat 
interrupted or lobed below; spikelets about 2 mm long, the bristles 
5 to 10 mm long; fertile lemma rather sharply but finely marked with 
cross-wrinkles (fig. 317). 
Open dry ground and dry woods, southwestern United States to 
Oaxaca; Hispaniola. 
