Plants annual or perennial; habit various. Culms 3-800 cm, annual, usually not woody. Leaves basal and/or cauline; sheaths usually open; ligules of hairs or membranous, membranous ligules often ciliate, cilia sometimes longer than the membranous base; blades occasionally pseudopetiolate, seldom disarticulating at maturity. Inflorescences terminal, sometimes also axillary, occasionally subterranean panicles; branches sometimes spikelike and secund, sometimes less than 1 cm; disarticulation usually below the glumes, sometimes at the base of the panicle branches, occasionally below the florets. Spikelets usually dorsally compressed, varying to terete or laterally compressed, with 2(3) florets, lower florets staminate, sterile, or reduced, upper florets usually bisexual; calluses not developed. Glumes usually membranous; lower glumes usually less than 1/2 as long as the spikelets, sometimes absent; upper glumes usually subequal to the upper florets, occasionally absent; lower lemmas similar to the upper glumes in length and texture; upper lemmas indurate, coriaceous, or cartilaginous, with a germination flap at the base, margins usually widely separated and involute at maturity, sometimes flat and hyaline; upper paleas similar to the upper lemmas in length and texture; lodicules short; anthers usually 3; stigmas usually red. Caryopses usually dorsally compressed or terete; embryos 1/2 or more the length of the caryopses. x = 9, 10.