Plants perennial; dioecious, staminate and pistillate plants similar; stoloniferous. Culms 10-70 cm. Leaves mostly cauline; ligules membranous, ciliate. Inflorescences terminal panicles, exceeding the upper leaves; branches appressed or ascending, usually spikelet-bearing to the base. Spikelets not disarticulating. Pistillate spikelets with 5-10 florets; lower glumes 1-5-veined, only the midveins conspicuous; upper glumes with 3 conspicuous veins, sometimes with 2-4 inconspicuous lateral veins; lemmas 3-5(6)-veined, unawned; paleas shorter than the lemmas, completely surrounding the ovaries, saccate basally, narrowing distally and surrounding the styles, intercostal region coriaceous, veins keeled, scabrous and puberulent, margins scarious. Staminate spikelets with 4-21 florets; lower glumes 1-veined; upper glumes 1-3-veined; lemmas conspicuously 3-veined, unawned; paleas equaling or slightly longer than the lemmas, linear, 2-veined, veins ciliolate. Lodicules 2, cuneate. x = 10. Name from the Greek allo, different, and lepis, scale or lemma, referring to the differing lemmas of the sexes.