Rhizomatous perennial with slender rhizomes producing woody, ovoid tubers c. 0.5–1 cm diam., with a grey-brown fibrous coat persisting for two years. Culms trigonous, smooth, to 90 cm high, 2–4 mm diam. Leaves not septate-nodulose, mostly from one-half to three-quarters as long as culm, to 4 mm wide. Inflorescence simple or compound, symmetrical (not thrown to one side), with 2–9 primary branches to 12 cm long; spikes ovoid, to 4 cm long, to 3 cm diam.; involucral bracts leaf-like, 1 or 2 much exceeding the inflorescence. Spikelets flattened, 5–10 per spike, 10–40 mm long, 2.5–3 mm wide in side view, 10–24-flowered; rachilla winged, persistent; glumes acute, with sides 1–3-nerved, very pale red-brown to orange-brown or red-brown, rarely very dark, 3–4 mm long; stamens 3; style 3-fid. Nut trigonous, broad-obovoid, greyish, c. 1.5 times as broad as long, c. 1.2 mm long, c. 0.8 mm diam. Flowers spring–summer.
MuM, VRiv, MuF. Also WA, NT, Qld, NSW. Malesia, Asia, Africa, ?South America. Known in Victoria only from the Kerang and Lalbert areas, but widespread in inland Australia, especially on floodplains on heavy clay soils. Occasionally a weed of cultivation, especially in irrigation areas.
