Plants annual or perennial; synoecious, monoecious, or dioecious; primarily herbaceous, habit varied. Culms annual, usually solid, sometimes somewhat woody, sometimes decumbent, often branched above the base. Leaves distichous; sheaths usually open; auricles usually absent; abaxial ligules usually absent, occasionally present as a line of hairs; adaxial ligules membranous, sometimes also ciliate, or of hairs, sometimes absent; bladessometimes pseudopetiolate; mesophyll radiate or non-radiate; adaxial palisade layer absent; fusoid cells usually absent; arm cells usually absent; kranz anatomy absent or present; midribsusually simple, rarely complex; adaxial bulliform cells present; stomata with triangular or dome-shaped subsidiary cells; bicellular microhairs usually present, with a long, narrow distal cell; papillae absent or present. Inflorescences ebracteate (Paniceae) or bracteate (most Andropogoneae) panicles, racemes, spikes, or complex arrangements of rames (in the Andropogoneae), usually bisexual, sometimes unisexual; disarticulation usually below the glumes, frequently in the secondary and higher order axes of the inflorescences. Spikelets bisexual or unisexual, frequently paired or in triplets, the members of each unit usually with pedicels of different lengths or 1 spikelet sessile. Glumes usually 2, equal or unequal, shorter or longer than the adjacent florets, sometimes exceeding the distal florets; florets 2, usually dorsally compressed, sometimes terete or laterally compressed; lower florets sterile or staminate, frequently reduced to a lemma; upper florets usually bisexual; lemmas hyaline to coriaceous, lacking uncinate hairs, often terminally awned; awns single; paleas of bisexual floretswell-developed, reduced, or absent; lodicules usually 2, sometimes absent, cuneate, free, fleshy, usually glabrous; anthers 1-3; ovaries usually glabrous; haustorial synergids absent; style branches2, free and close or fused at the base. Caryopses: hila usually punctate; endosperm hard, without lipid; starch grains simple; embryos large in relation to the caryopses, usually waisted; epiblasts usually absent; scutellar cleft present; mesocotyl internode elongated; embryonic leaf margins usually overlapping, rarely just meeting. x = 5, (7), 9, 10, (12), (14).