Andropogon virgatus Desv. ex Ham.

Andropogon spathiflorus (Nees) Kunth, Enum. 1 : 496. 1833
"f Andropogon virgaius Desv.; Hamilt. Prodr. 9. 1825.
Hypogynium spathiflorum Nees, Agrost. Bras. 366. 1829.
"? Anatherum. virgatuin Desv. Opusc. 71. 1831.
Andropogon inermis Steud. Syn, Gram. 390. 1854.
Analherum spathiflorum Griseb. Cat. PI. Cub. 236. 1866.
Anatherum inerme Griseb. Cat. PI. Cub. 236. 1866.
Andropogon spathiflorus inermis Hack, in DC. Monog. Phan. 6 : 398. 1889.
Sorgum spathiflorum Kuntze, Rev. Gen. 792. 1891.
A densely tufted perennial with intravaginal innovations. Stems up to 1 m. tall, simple below, much-branched above; leaf-sheaths keeled, compressed; blades of the innovations up to 4 dm. long, 1.5-2 mm. wide, those of the stem a little shorter and broader, glabrous or ciliate at the base; spathes acute, 1-1.5 cm. long, scarious, glabrous, brown, usually 2-3 times as long as the slender puberulous peduncle of the raceme; spike-like racemes dense, 6-13 mm. long, the rachis straight, the internodes and pedicels about one third as long as the sessile spikelets, glabrous; sessile spikelet 2.5-3.5 mm. long, linear-lanceolate, the first scale with narrowly infolded margins and aculeate keels, nerveless, excepting the keels, flat on the back, the second scale 1-nerved, the third scale shorter than the first, acute, l-nerved, ciliolate, the fourth scale 2-toothed, awnless, or merely mucronate between the teeth, the flower pistillate with 3 rudimentary stamens; pedicellate spikelet equaling the sessile one, lanceolate, strongly colored, the first scale very acute, 3-nerved, the fourth scale entire, awnless^ the 3 stamens perfect.
Type locality : In plains, behind Ypanema, Sao Paulo, Brazil.
Distribution : Cuba ; Haiti ; Porto Rico ; Costa Rica ; also in tropical South America.

Perennials, Terrestrial, not aquatic, Rhizomes present, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes solid or spongy, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, L eaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Ligule present, Ligule a fringed, ciliate, or lobed membrane, Inflorescence terminal, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence single raceme, fascicle or spike, Flowers bisexual, Spikelets pedicellate, Spikelets sessile or subsessile, Spikelets dorsally compressed or terete, Inflorescence or spikelets partially hidden in leaf sheaths, subtended by spatheole, Spikelet less than 3 mm wide, Spikelets with 2 florets, Spikelet with 1 fertile floret and 1-2 sterile florets, Spikelets paired at rachis nodes, Spikelets in paired units, 1 sessile, 1 pedicellate, Spikelets bisexual, Spikelets disarticulating below the glumes, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes distinctly un equal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes keeled or winged, Glumes 1 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma glabrous, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma margins thin, lying flat, Lemma straight, Palea shorter than lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis.

Andropogon virgatus là một loài thực vật có hoa trong họ Hòa thảo. Loài này được Desv. mô tả khoa học đầu tiên năm 1825.