Annual. Culms slender, creeping, rooting at lower nodes, ascending to 10–50 cm tall. Leaf sheaths glabrous, one margin densely ciliate; leaf blades lanceolate, 2–6 × 0.3–1.2 cm, glabrous or loosely hispidulous, base subcordate, margins scabrous, pectinate-ciliate at base; ligule ca. 1 mm, ciliate. Inflorescence pyramidal, axis 1–8 cm; racemes 3–6(–12), 0.5–4 cm, spreading; rachis triquetrous, scabrous; spikelets paired, crowded, pedicels setose. Spikelets ovate or ovate-elliptic, 2–2.5 mm, usually glabrous, acute; lower glume cufflike, 1/8–1/4 spikelet length, thinly membranous, veinless or obscurely 3-veined, truncate or rounded; upper glume (5–)7–9-veined; lower lemma 5-veined, palea well developed; upper lemma broadly elliptic, 1.8–2 mm, finely rugose, apiculate. Fl. and fr. summer–autumn. 2n = 14, 18.