Plants perennial or annual; cespitose or tufted. Culms 4-65 cm, erect, slender. Leaves linear, flat, usually becoming folded and filiform; ligules membranous, ciliate. Inflorescences terminal, unilateral linear spikes or spikelike racemes, with 1 spikelet per node, exceeding the leaves; rachises visible, not concealed by the spikelets. Spikelets appressed, in 2 rows along 1 side of the rachises, with 3-20 bisexual florets, distal florets sterile or staminate; disarticulation above the glumes and between the florets. Glumes unequal, 1(3)-veined; lemmas 1-3-veined, backs slightly keeled or rounded, apices lobed or bifid, mucronate or awned from between the lobes, lateral veins sometimes also excurrent, awns usually straight; anthers 1-3. x = 10. Name from the Greek treis, three, and pogon, beard, alluding to the hairs at the bases of the three lemma veins found in many of its species.