Small, tufted, leafy annual with reddish roots. Culms triquetrous, smooth, 1–20 cm high, to 1.5 mm diam. Leaves not septate-nodulose, usually longer than culms, 1–2 mm wide. Inflorescence densely head-like, 6–18 mm diam.; involucral bracts leaf-like, 5–7 or more, spreading, very much longer than inflorescence, often a few smaller bracts protruding from the head. Spikelets flattened, very numerous per cluster, 3–5 mm long, 1.5–2 mm wide in side view, 8–20-flowered; rachilla not winged, persistent; glumes acute, short-mucronate, with sides 1–2-nerved, white to pale brown with conspicuous green keel, c.2 mm long, c. 0.5 mm wide; stamens 1 or 2; style 2(–3)-fid. Nut dorsally flattened with a flat or concave face against the rachilla, or sometimes trigonous, obovoid to ellipsoid, pale brown, from one-half to one-third as long as glume, 0.8–1 mm long, 0.2–0.5 mm diam. Flowers spring–summer.
MuM, MSB, RobP, MuF, HNF. All mainland States. Asia, Africa, Europe. On banks and seasonally wet floodways of the Murray River between Mildura and Swan Hill, with a distant occurrence upstream near Yarrawonga; on clayey soils in open positions.
