Plants perennial; usually densely cespitose, often with short, stout rhizomes. Culms 24-70 cm, not woody basally, erect, geniculate, or decumbent and rooting at the lower nodes, not branched from the aerial nodes; nodes usually 2-3, glabrous or puberulent; lower internodes glabrous. Leaves mainly basal; sheaths glabrous or sparsely hirsute; ligules 0.1-0.4 mm, of hairs, often with marginal tufts of long hairs; blades 2-12 (19) cm long, 0.5-2.5 mm wide, flat to involute at maturity, hairs usually present basally. Panicles with 1-3 (6) branches, these racemose on 2-8.5 (12.5) cm rachises or digitate; branches 13-50 (75) mm, persistent, arcuate, scabrous, without papillose-based hairs, with 40-130 spikelets, terminating in a spikelet; disarticulation above the glumes. Spikelets pectinate, with 1 bisexual and 1 rudimentary floret. Glumes mostly glabrous or scabrous, midveins sometimes with papillose-based hairs; lower glumes 1.5-3.5 mm; upper glumes 3.5-6 mm; lowest lemmas 3.5-6 mm, pubescent at least basally, 5-lobed, central and lateral lobes veined and awned, awns 1-3 mm, central awns flanked by 2 membranous lobes; lower paleas about 5 mm, shallowly bilobed, veins excurrent for less than 1 mm; rachilla segments subtending second florets with a distal tuft of hairs; anthers 1.7-2.9 mm, yellow or purple; upper florets sterile, 0.9-3 mm, lobed almost to the base, lobes rounded, 3-awned, awns equal, 1-3 mm. Caryopses 2.5-3 mm long, about 0.5 mm wide. 2n = 20, 28, 35, 40, 42, 60, 61, 77, 84.
Alta., B.C., Man., Ont., Sask., Wis., Wyo., Conn., Fla., S.C., N.Mex., Tex., N.Y., Nev., Colo., Calif., Kans., N.Dak., Nebr., Okla., S.Dak., Ill., Iowa, Ariz., Idaho, Maine, Mass., Ohio, Utah, Mo., Minn., Mich., Mont.
Bouteloua gracilis grows in pure stands in mixed prairie associations and disturbed habitats, usually on rocky or clay soils and mainly at elevations of 300-3000 m. Its native range extends from Canada to central Mexico; records from the eastern portion of the Flora represent introductions.
Bouteloua gracilis is an important native forage species and also an attractive ornamental.
"decumbent" is not a number.