48 
23. A.divergens. (A. Schiediana var. winor Vasey, Torr. Bull. x. p, 28.) Culms 
12 to lsinches high, erect, simple; leaves involute, 6 to 10 inches long; panicle 5 to 
7 inches long becoming pyramidal, sheathed at base by the uppermost leaf; brauches 
at first erect spreading, becoming divergent, 1 to 3 inches long, solitary above, the 
lower divided at the base into 3 or 4 nearly equal divisions (appearing verticillate), 
again divided above the middle; spikelets diverging ; empty glumes 3 to4 lines long; 
floral glume 5 lines, becoming somewhat twisted in age ; the lateral awns wanting or 
nearly so; middle awn 5 to 6 lines long, straight..—Texas to Arizona. 
Smaller and less robust than A. Schiediana, not having the long naked branches of 
that species. 
24. A. scabra Kth. (Chapm. Fl. 8. States, Suppl., p. 663.) Culm without nodes, 
except at the base, from creeping root-stock 14 to 3 feet high; leaves radical, seta- 
ceously attenuated, panicle large, spreading; the branches single or 2 to 5 in a clus- 
ter, long (6 to 8 inches), naked below; spikelets appressed; glumes awn-pointed, 
about 5 lines long; floral glumes about 5 lines long; middle awn 9 to 12 lines long; 
the lateral ones 2 to 6 lines long; stamens 2.—Florida (Dr. Chapman). Apparently 
the same from Mexico, Renarkable for its long scapiform culms. Kunth’s species is 
described as without lateral awns. 
25. A. Orcuttiana Vasey. Bull. Torr, Club, x1. p. 25. Culms about 2 feet 
high, stout below, above becoming slender, very leafy; leaves near the base with 
loose open sheaths and rather broad blades, the upper narrow, becoming involute, 5 
to 8 inches long or more; panicle, long and open, 4 to 5 inches long; branches rather 
distant, mostly single, flexuous, the lower ones about 3 inches long, with the lower 
half naked ; lower glume about 5 lines long, the upper one-quarter shorter; flowering 
glume with the awn 9 lines long, the lateral awns obsolete or nearly so; the main 
awn bent near the middle and twisted below.—Southern California (C. 2. Orcutt) 
and Arizona (.M. . Jones.) The panicle is small for the size of the plant, and com- 
paratively few flowered. It approaches Aristida Schiediana. 
26. A. Ploridana Chapm. (Streptachne Floridana Chapm.; Fl. 8. States, p. 554.) 
Culms 2 feet high, simple, slender, erect; leaves long, filiforin, convolute, smooth ; 
sheaths hairy ar throat; panicle 1 foot long, narrow, erect, the branches in pairs, 
scattered ; spikelets short-stalked ; empty glumes equal, linear, purple, 1-nerved, the 
lower awn-pointed; palet (floral glume) raised on a slender bearded stalk, linear- 
subulate, gradually tapering into the long compressed curved awn; uo lateral 
awns.—South Florida (Dr. Blodgett). 
§ 2. Awns united and articulated to the floral glume. 
27, A.tuberculosa Nutt, (Gray’s Manual, 6th ed., p. 641.) Culms from an annual 
root, 10 to 18 inches high, branched below ; panicles racemose, loose, rigid, about 6 
inches long; the branches rather distant, the lower in pairs, one short and few-flowered, 
the other elongated (2 to 3 inches long) and many-flowered ; empty glumes Linch long, 
awn-tipped; floral glume about 10 lines long to the separation of the awns, a rather 
long, sharp, densely-hairy stipe,and a distinct articulation at its apex, the proper 
glume about 5 lines long, the prolongation above twisted 3 or 4 coils to the division 
of the nearly equal bent and divergent (sometimes reflexed) awns, which are 14 to 
2 inches long.—Massachusetts to Minnesota and southward. 
28. A. desmantha Trin. & Rupr. Gram, Agrost. p. 109. Culms 14 to 2 feet 
high, much branched; leaves convolute, 6 to 10 inches long, panicle rather narrow, 
erect, 4 to 6 inches long; the branches mostly in twos, one short, the other longer (2 
to 3 inches), naked below, the spikelets fascicled above, short-pediceled ; empty 
glumes nearly equal, 7 to 8 lines long, subulate-awned at apex ; floral glume 4 to 5 
lines long, including the sharp stipe,and to the articulation; the junction of the 
awus near or at the articulation, and the curving and spreading awns about 1 inch 
long.—Texas and Indian Territory. 
29, A. Californica Thurb. Bot. Cal. 1. p. 289. (4, Jonesii Vasey.) Annual; 
culms 5 to 10 inches high, densely tufted; much branched; often geniculate below ; 
