Plants annual or perennial; rhizomatous or cespitose. Culms annual, not woody, ascending to erect or decumbent, sometimes branching above the base; internodes hollow. Sheaths open, margins overlapping for most of their length; collars without tufts of hair on the sides; auricles absent; ligules membranous, entire or toothed, sometimes shortly ciliate, those of the lower and upper cauline leaves usually similar; pseudopetioles absent; blades linear to narrowly lanceolate, venation parallel, cross venation not evident, without arm or fusoid cells, cross sections non-Kranz, epidermes without microhairs, not papillate. Inflorescences terminal, spikelike racemes, spikelets subsessile, solitary at all or most nodes; pedicels to 2.5 mm. Spikelets terete to slightly laterally compressed, with (3)5-24 florets, distal florets sometimes reduced, sterile; disarticulation above the glumes, beneath the florets; rachillas prolonged beyond the base of the distal floret. Glumes unequal, 1/2 as long as to equaling the adjacent lemmas, lanceolate, lower glumes 3-7-veined, upper glumes 5-9-veined; florets subterete to slightly laterally compressed; calluses glabrous, not well developed; lemmas lanceolate, usually membranous, rounded dorsally, (5)7-9-veined, veins not converging distally, inconspicuous, apices entire, obtuse or acute, unawned or terminally awned; paleas shorter than to slightly longer than the lemmas; lodicules 2, not veined, distal margins ciliate or the apices puberulent; anthers 3; ovaries with hairy apices; styles 2, bases free. Caryopses with hairy apices, longitudinally grooved; hila linear; embryos about 1/6 the length of the caryopses. x = 5, 7, 9.