Annuals, occasionally perennials, 4-65 cm; caespitose, or basal internodes elongated and rooting; rhizome, when present, short, stoloniferous. Stem 0.3-2.5 mm diam., trigonous above. Leaves from 1/2 of stem length to much exceeding it, sheaths 15-50 mm; ligule 0; blades 7-20 cm, 1.5-3 mm wide. Inflorescence from a single cluster of digitate spikes to small anthelodium, elongate primary branches 0-4, 15-50 mm; cluster of spikes with 3 - 100 spikes, 15-30 mm, 1-4 foliose bracts up to 15 cm long; spikes 4-30 x 1-3 mm, rachis nearly quadrangular, with or without wings, with 8-40 glumes; stamens 1-2, stigmas 2; nut lenticular, edge towards rachis.