Plants annual, biennial, or perennial; loosely cespitose or tufted. Culms 30-120 cm tall, 2-4 mm thick, erect or decumbent. Sheaths usually densely, often retrorsely, hairy, hairs sometimes confined to the throat; auricles absent; ligules 1-4 mm, glabrous or pilose, obtuse, lacerate to erose; blades 4-30 cm long, 3-10 mm wide, flat, glabrous or hairy on both surfaces. Panicles 9-28 cm, usually open, erect or nodding; lower branches shorter than 10 cm, 1-4 per node, spreading or ascending, with up to 5 spikelets variously distributed. Spikelets (17)20-40 mm, shorter than at least some pedicels and branches, elliptic to lanceolate, strongly laterally compressed, not crowded or overlapping, with 4-12 florets. Glumes smooth or scabrous, glabrous or pubescent; lower glumes 7-12 mm, 5-7(9)-veined; upper glumes 9-17 mm, 7-9(11)-veined, shorter than the lowest lemma; lemmas 11-20 mm, lanceolate, laterally compressed, strongly keeled, usually glabrous, sometimes pubescent distally, smooth or scabrous, 9-13-veined, veins often raised and riblike, margins sometimes conspicuous, hyaline, whitish or partly purplish, apices entire or toothed, teeth acute, shorter than 1 mm; awns absent or to 10 mm; anthers 0.5-1 mm in cleistogamous florets, 2-5 mm in chasmogamous florets. 2n = 42.
D.C, Kans., N.Dak., Okla., Pacific Islands (Hawaii), Fla., N.J., N.Mex., Tex., La., Nebr., Tenn., N.C., S.C., Pa., N.Y., Nev., Va., Alta., Nfld. And Labr. (Nfld.), Ont., Colo., Calif., Ala., Ark., Ill., Ga., Iowa, Ariz., Md., Ohio, Utah, Mo., Miss., Ky., Oreg., S.Dak.