514 
5. A. gracilis Ell. Culms branched-near the base, 3 to 5 dm. high: panicles 1 to 
2 dm, long: spikelets 5 to 6 mm.long; empty glumes nearly equal, equaling -or 
slightly shorter than the floret; middle awn about lem. long; lateral awns usually 
shorter.—Light soil, eastern Texas and eastward. 
6. A. Nealleyi Vasey. Culms slender, mostly simple, 4 to 6 dm. high: panicle 1 
to 1.5 dm. long: spikelets about 8 mm. long; the floret nearly equalled by the second 
empty glume; the first one-half to three fourths as long; lateral branches slightly 
shorter, united in the tapering apex of the floral glume and twisted.—Among rocks, 
southwestern Texas. 
=== Panicle rather dense, spikelets 4 or moreon each branch, 
7. A. bromoides HBK. Culms in small tufts, branching below, 1 to 8 dm. high: 
leaves few and short: panicle 6 to 12 em. long: spikelets 7 to 9 mm. long; floral 
glume spotted, slightly exceeding the second empty glume, nearly twice as long as 
the first; awns nearly equal, about 1 cm. long, divided to the base.—High plains, 
western Texas and westward to California, 
8. A. dispersa Trin. & Rupt. Culms branching, 3 to 6 dm, high: leaves flat or 
involute, 1 to3dm. long: panicle somewhat loose or interrupted, 1 to 2 dm, long: 
spikelets 7 to 9 mm. long; first empty glume two-thirds as long as the floret; second 
empty glume about equaling the floret; awns 9 to 15 mm. long.—Mountains, west- 
ern Texas and westward. 
+ + Spikelets larger, 1 to 2 cm. long; awns 2 to Sem, long. 
++ Branches erect, making the spikelike panicle nearly continuous. 
9. A. Reverchoni Vasey. Culms3 to4dm. high, simple: radical leaves numerous, 
1to 2 dm. long, setaceously pointed, curved: panicle 1 to 2. dm. long, slender and 
strict but closely flowered: spikelets 11 to 14 mm. long; floral glume narrow and 
slightly twisted above, slightly exceeding the unequal, mucronate or toothed, empty 
glumes; awns 2 to 3 cm. long.—Rocky ravines and hills, western Texas, 
10. A. Arizonica Vasey. Culms rigid, 4 to 7 dm. high: leaves flat or involute, 
nearly straight: panicle strict, 2 to 3 dm. long: spikelets about 11 mm. long; first 
empty glume 3-nerved; second empty glume t-nerved, longer, about equaling the 
floret; floral glume narrow and twisted above; awns 2 to 3 em. long.—Sandy plains, 
Texas to Arizona. 
+ ++ Branches often slightly spreading: panicle somewhat interrupted, 
11. A. purpurascens Poir. Culms 4 to 6 dm. high, rarely branching: radical 
leaves mostly flat, 2 to 3 dm. long: panicle slender, usually somewhat interrupted, 1 
to 1.5 dim. long: spikelets 8 to 10 mm. long; empty glumes l-nerved; the first longer 
than the second, both exceeding the spotted tloret; awns 2 to 3 em. long, divided to 
the base.—Sandy land, Texas and eastward, Var. MINOR Vasey has more branched 
culms, and shorter spikelets and awns.—Low sandy land. 
12, A. lanata Poir. Culms rather stout, simple, 5 to 10 dm. high: leaves mostly 
flat, 3 to 6dm. long; sheaths lanate: panicle rather loose, erect or nodding and 
secund; branches mostly in twos, one long and naked below, the other short: spike- 
lets about 12 mm. long; first empty glume exceeding the floret; second empty glume 
about equaling the floret; middle awn curved backwards, 2 cin. long; lateral awns 
usually one-third shorter.—Central Texas to Florida and along the coast region to 
New Jersey. 
++ ++ ++ Panicle loose and interrupted: awns 3 to S em. long. 
13. A. fasciculata Torr. Culms 2 to 5dm. high, rarely branched: leaves short, 
involute, scabrid: panicle 1 to 2 dm. long, slender and flexnous; branches erect or 
slightly spreading, 1 to3 em. long: spikelets 12 to 15mm. long; empty glumes 1- 
nerved, somewhat bilid and mucronate or irregularly toothed at the apex; the first 
