Bouteloua rigidiseta (Steud.) Hitchc.

Aegopogon rigidisetus Steud. Syn. Gram. 146. 1854
Aegopogon cenchroides abortivus Fourn. Mex. PI. Gram. 72. 1881.
Aegopogon cenchroides niultisetus Fourn. Mex. PI. Gram. 72. 1881.
Aegopogon gracilis Vasey, Bull. Torrey Club 13 : 230. 1886.
Stems 1-5 dm. tall, slender; leaf-sheaths smooth and glabrous; blades up to 1 dm. long, usually flat, 1-2 mm. wide, glabrous beneath, puberulent on the upper siuiace; inflorescence 2-8 cm. long, sometimes interrupted below; spikelet-clusters 3-4 mm. long, exclusive of the awns and hispid peduncle, of usually 3, or sometimes 2, spikelets on hispid pedicels, the sessile or short-pedicellate spikelet perfect, the others staminate or empty, one often reduced in size; empty scales strongly scabrous, linear to oblong or cuneate, awned from the 2-lobed apex, the awn from shorter than to longer than the scale, rarely twice its length, the lobes very short, deltoid and merely acute to subulate, awned and one half as long as the scale or more; flowering scales 3-nerved, 3-lobed and 3-awned at the apex, the midnerve extending into a hispidulous terete awn as long as or longer than the scale, the lateral lobes with usually a minute tooth at the base of the awn.
Type locality : Cumana, Venezuela.
Distribution : California, Mexico, and Guatemala ; also in South America.

Bouteloua rigidiseta (Steud.) Hitchc. Jour. Wash. Acad 23:453. 1933.
Aegopogon rigidiselus Steud. Syn. Gram. 146. 1854.
Bouteloua texana S. Wats. Proc. Am. Acad. 18: 196. 1883. (Type from Texas, Berlandier 1535.) Polyodon texanus Nash in Small, Fl. SE. U. S. 138, 1327. 1903. (Based on Bouteloua texana S. Wats.)
Perennial; culms densely tufted, erect, 10-40 cm. tall, glabrous; sheaths glabrous, or hispid at the throat, the lower ones longer than the internodes, the upper ones longer than the lower but shorter than the internodes; blades involute, or flat toward the base, curved or flexuous, attenuate, 2-12 cm. long, or longer on the innovations, 1-2 mm. wide, glabrous or pilose, especially on the upper surface, the margins scabrous; spikes 5-9, about 1 cm. long, spreading or recurved, falling entire, bearing 2-4 approximate spikelets; spikelets appressed to the short rachis; first glume narrow, almost subulate, 3-4 mm. long, the second much broader, 7-8 mm. long, acuminate, densely pubescent on the lower part of the nerve; lemma 5-6 mm. long, glabrous, the tip with 4 slender teeth, awned from between the teeth, the awns 3-4 mm. long, flattened, scabrous; rudimentary florets 2-3, the awns about 8 mm. long, flattened, scabrous.
Type locality: Texas (Drummond) .
Distribution: Dry prairies and rocky hills, Oklahoma, Texas, and northern Mexico.

Perennials, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smo oth, glabrous, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades more or less hairy, Ligule present, Ligule a fringed, ciliate, or lobed membrane, Inflorescence terminal, Inflorescence with 2 or more spikes, fascicles, glomerules, heads, or clusters per culm, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence with 2-10 branches, Inflorescence branches 1-sided, Flowers bisexual, Spikelets sessile or subsessile, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Inflorescence branches deciduous, falling intact, Spikelets secund, in rows on one side of rachis, Rachilla or pedicel glabrous, Glumes present, empty bra cts, Glumes 2 clearly present, Glumes distinctly unequal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes 1 nerved, Lemma coriaceous, firmer or thicker in texture than the glumes, Lemma 3 nerved, Lemma glabrous, Lemma apex dentate, 3-5 fid, Lemma teeth unequal. central tooth longer, Lemma distinctly awned, more than 2-3 mm, Lemma with 3 awns, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea shorter than lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Bouteloua rigidiseta là một loài thực vật có hoa trong họ Hòa thảo. Loài này được (Steud.) Hitchc. mô tả khoa học đầu tiên năm 1933.