47 
1 or 2 inches long; panicle 3 to 4 inches long, thin; branches erect or becoming 
spreading, few-flowered, mostly in twos below, with short capillary pedicels; empty 
glumes variable, 4 to 6, 4to 8, or 5 to 10 lines respectively; awus nearly equal, capil- 
lary 1 to 2} inches long. 
Var. Hookert Trin. More robust, 14 feet high, with coarser and longer leaves, 
panicle more spreading than in the preceding and more numerously flowered; spike- 
lets larger, glumes longer, awns varying 2} to 44 inches long. 
Var. CALIFORNIA Vasey. Culms tall, 2 to 24 feet high, with long leaves (often 1 
foot long), panicle flexuous, 5 to 7 inches long, lower branches often 5 to 7 at the 
nodes, 1 to 3 inches long, spreading, capillary, and naked below; empty glumes 3 to 
6 lines respectively, awns about 2 inches long.—Western Texas to California. 
Var. MICRANTHA. Culm 1 to 1} feet high, slender, flexuous, leaves much as in Ist 
var., but culms usually decumbent at base and branching, the branches mostly in twos 
or threes, capillary, few-tlowered, spreading or reflexed, spikelets usually smnaller than 
in any other form (lower 3 to 4, upper 4 to 6 lines long).—Western Texas. 
19. A. Arizonica Vasey. Bull. Torr. Club, xu. p.27, Perennial, culms 2 to 2} 
feet high, erect, unbranched, stout; leaves flat, becoming involute, 6 to 12 inches 
long; panicle strict erect, 6 to 10 inches long, the lranches mostly single or in twos, 
erect, about 2 inches long, each 2- to5-flowered ; spikelets approximate, sessile, or nearly 
so; empty glumes nearly equal, 6 to 8 lines long, the lower one 3-nerved, awn pointed; 
flowering glume 7 to 8 lines long, twisted below the awns, hispid, awns nearly equal, 
spreading, 10 to 12 lines long.—New Mexico and Arizona. Differs from A, purpurea in 
its larger size, close, rigid panicle, and nearly equal glumes, the lower one 3-nerved. 
* * * *  Panicles spreading, branches longer. 
20. A. Havardii Vasey. Bull. Torr. Club, xur. p. 27. Culms about 1. foot 
high, erect, rather slender; leaves setaceous,3 to 6 inches long, about 6 on the culm ; 
glumes nearly equal, about 5 lines long, l-nerved, narrow, acuminate ; flowering glume 
about as long, with a short hairy callus, tapering to the apex; awns erect, spreading, 
nearly equal, 6 to 7 lines long; the panicle usually 4 to 6 inches long, open, the 
branches at first erect, in age becoming horizontal or reflexed, pyramidal, in pairs or 
fascicled below; lower branches 2 inches long, naked below, spikelets rather distant.— 
Western Texas (Dr. Havard) and New Mexico. Possibly this includes 4. Palmeri. 
21. A Humboldtiana Trin. & Rupr. Gram. Agrost., p. 118. (4. divaricata H. 
B.K.) Perennial, tufted, culms erect, simple, 1 to 2 feet long; leaves narrow or convo- 
lute, rather short and rigid, in twos and threes, the lower often 5 or 6 inches long, 
flower-bearing above the middle, widely spreading except those included in the 
sheath, few-flowered ; empty glumes nearly equal, awl]-pointed, 5 to6 lines long; flow- 
ering glume slightly shorter; awns subequal, lateral, 4 to 5 lines, middle one 6 to 8 
lines long. —Texas to Southern California and Mexico, 
Var. MINOR. Smaller, culms about 1 foot high; panicle exserted, 5 to 6 inches long, 
pyramidal, branches 2 to 3 inches long; empty glumes 4 to 5 lines long, awns nearly 
equal, 4 to 5 lines long.—Texas, Arizona, to Calitornia, 
* * * * * Lateral awns minute or wanting. 
99. A Schiediana Trin. & Rupr. Gram. Agrost. p. 120. Perennial, culms 2 to 
24 feet high, erect; leaves filiform-convolute, 6 to 12 inches long, glabrous; pan- 
icle ¢ to 1 foot long, depauperate, the branches solitary or in pairs, distant, 3 to 5 
inches Jong, suberect or widely spreading, rigid, often one-sided, flowering beyond 
the middle; empty glume nearly equal,4 to 5 lines long; flowering glume 6 to7 
lines long, the apex tapering and twisted; lateral awns minute, one-half line long 
or less, ereet the middle one spreading, 4 to 6 lines long.—-Texas, New Mexice to 
Mexico. 
