Perennial grasses with flat and usually short rigid leaf-blades and numerous slender alternate spikes. Spikelets 1-flowered, almost sessile, the rachilla extended and bearing a small scale which is usually awned. Scales 3 or 4; the 2 lower empty, unequal, narrow, acute; third broader, fertile, 3-nerved, slightly 2-toothed at the apex, bearing an erect awn; the fourth empty, small, awned; palet 2-keeled. Stamens 3. Styles distinct. Stigmas plumose. Grain linear, free, enclosed in the rigid scale. [Greek, naked-beard, referring to the prolongation of the rachilla.]

Six species, all but one American. Type species: Andropogon ambiguus Michx.

Spikes bearing spikelets their whole length; awn longer than flowering scale.




Spikes bearing spikelets above the middle; awn shorter than flowering scale.




60 Gymnopogon Beauv Agrost 41 Pl 9 F 3 1812 545

1. Gymnopogon Ambiguus (Michx.) B.S.P. Broad-Leaved Or Naked Beard-Grass

Fig. 545

Andropogon ambiguus Michx. Fl. Bor. Am. I: 58. 1803. Gymnopogon racemosus Beauv. Agrost. 164. 1812. G. ambiguus B.S.P. Prel. Cat. N. Y. 69. 1888.

Culms 12'-18' tall, erect, or decumbent at the base, simple or sometimes sparingly branched, smooth and glabrous. Sheaths short, glabrous, excepting a villous ring at the summit, crowded at the base of the culm; ligule very short; blades 1'-4' long, 2"-6" wide, lanceolate, acute, cordate at the base, spreading, smooth or a little scabrous above; spikes slender, spikelet-bearing throughout their entire length, at first erect, the lower 4'-8' long, at length widely spreading; spikelets, exclusive of awns, 2"-2 1/2" long; first scale snorter than the second; third scale exceeded by the second, the callus at the base hairy, the awn 2"-3" long.

In dry sandy soil, southern New Jersey to Kansas, south to Florida and Texas. Aug.-Oct.

2. Gymnopogon Brevifolius Trin. Short-Leaved Beard-Grass

Fig. 546

Gymnopogon brevifolius Trin. Unifl. 238. 1824.

Culms 1°-2° long, from a decumbent base, simple, slender, smooth and glabrous. Sheaths shorter than the internodes, sometimes crowded near the middle of the culm; ligule very short; blades 1'-2' long, 1"-4" wide, usually spreading, lanceolate, acute, cordate at the base; spikes very slender, spikelet-bearing above the middle, the lower 4'-6' long, at first erect, finally widely spreading; spikelets, exclusive of the awns, 1 1/2" long; first scale shorter than the second; third scale equalling or exceeded by the second, short-awned, sparingly villous or glabrous, the callus hairy.

In dry soil, New Jersey to Florida, west to Mississippi. Aug.-Oct.

2 Gymnopogon Brevifolius Trin Short Leaved Beard G 546