Perennial, with creeping or floating ± spongy rhizomes; culms 10-60 cm high, prostrate and rooting at the lower nodes. Leaf-blades 5-30 cm long, 2-10 mm wide, flat or folded, setaceously acuminate. Inflorescence 5-30 cm long; racemes 0.54 cm long, usually less than their own length apart, their rhachis narrowly winged from a triquetrous midrib, 0.5-1 mm wide, glabrous or sparsely ciliate. Spikelets ovate, 1.6-2.6(2.9) mm long; lower glume truncate, a quarter to a third the length of the spikelet; upper glume two-thirds to four-fifths the length of the spikelet; lower floret with a palea, its lemma as long as the spikelet, the nerves not raised; upper lemma granulose.