Plants annual or perennial; cespitose, sometimes stoloniferous, occasionally with rhizomes. Culms 2-60 cm. Sheaths open, throats glabrous or long-ciliate; ligules of hairs, or membranous and ciliate, or ciliolate; blades flat or rolled, glabrous or villous. Inflorescences terminal, sometimes also axillary, panicles, spikes, or racemes. Spikelets with 2-5(10) florets, distal florets reduced; disarticulation above the glumes and between the florets. Glumes exceeding or exceeded by the florets, herbaceous, 3-5-veined, glabrous or scabridulous, sometimes with stiff, papillose-based hairs, glume apices acute or acuminate; calluses glabrous; lemmas herbaceous, with acute or clavate hairs in marginal rows or variously scattered, lemma apices unlobed, acute to long-acuminate; paleas sometimes with tufts of hairs on the margins; lodicules 2, obtriangular, glabrous or with bristles, 1-3-veined, lodicule apices at least as thick as the base; anthers 3, 0.3-3.1 mm. Caryopses 0.7-2.2 mm long, 0.4-1.1 mm wide; pericarp poorly separable, dull, smooth or rugulose, glabrous; embryos 1/3-1/2 as long as the caryopses; hila punctiform. x = 6. Desvaux did not explain the etymology of Tribolium. It may be derived from the Greek trilobos, a name of various prickly plants (Quattrocchi 1999) or the Latin tria, three, and bolus, a fiery meteor in the form of an arrow, referring to the appearance of the mature spikelets with their three florets and coarsely hairy glumes, which, like the lemmas, may be awned or acuminate (Clifford 1996).