This is a tufted perennial grass. Stems are stout below with distichous leaves and very slender above, 2 to 3-1/2 feet long.
The leaf-sheaths are distichous and towards the base of the stem are 1/2 inch broad, compressed, keeled and with scattered tubercle-based hairs. The ligule is a short membrane fringed with close set hairs.
Fig. 155.—Andropogon asper.
Leafy shoot, a bit of the stem with leaf-sheaths and a bit of the leaf.
The leaf-blades are broad, distinctly linear, acute or acuminate, coriaceous, glabrous or softly hairy on both the surfaces, with a slender midrib which bears short stiff tubercle-based hairs all along, and margins with similar hairs, but a few leaves towards the base are longer, and varying in length from 12 to 18 inches and in breadth from 1/2 to 3/4 inch.
The panicle is somewhat narrow, 7 to 8 inches long, branches are very slender, whorled, usually with only one spike consisting of a sessile and two pedicelled spikelets.
The sessile spikelets are 1/4 inch long, laterally compressed, with a long callus villous all round, and bisexual. The first glume is coriaceous, linear-oblong, strongly compressed above and with a few stiff short bristles beneath the tip. The second glume is linear, oblong, coriaceous, with an awn as long as itself or shorter, keeled and with short stiff bristles on the keel and on the sides above the middle. The third glume is hyaline, narrow, obtuse, shorter than the second, 2-nerved, ciliate. The fourth glume is the linear, hyaline, 3-nerved base of the awn; the awn is 1-1/2 to 2-1/2 inches and bent at about the middle.
The pedicelled spikelets are about 1/3 inch, narrowly lanceolate, male or neuter and with short rusty hairs on both the margins of the pedicel and a semi-circular tip. The first glume is thin, 2-toothed or not at the tip, awned, awn being as long as itself or longer, 7-nerved, ciliate at the sides from base to tip; the nerves are either equidistant or the lateral nerves nearer the margin. The second glume is lanceolate-acuminate, not awned, 3-nerved, margins hyaline, and ciliolate. The third glume is hyaline, linear-oblong, 2-nerved, ciliolate. The fourth glume is linear or linear-lanceolate, hyaline, nerveless or 1-nerved.