Robust tussock-forming perennial with short thick rhizome. Culms 30–150 cm high, trigonous, smooth, to 10 mm diam. Leaves strongly septate-nodulose, often longer than culms, 5–40 mm wide. Inflorescence compound with 6–10 primary branches to 20 cm long; spikes ovoid to cylindric, 1–3 cm long and diam.; involucral bracts leaf-like, 5–10 much exceeding inflorescence, to 150 cm long. Spikelets terete to flattened, numerous per spike, 4–20 mm long, 1–2.5 mm wide in side view, 4–10-flowered; rachilla broadly winged; spikelet falling as unit; glumes acute, with sides 2–4-nerved, red-brown, 4–6.5 mm long; stamens 3; style 3-fid. Nut trigonous, very narrow-ellipsoid, dark grey-brown to blackish, c. two-thirds as long as glume, 2.5–3 mm long, c. 0.7 mm diam. Flowers spring–summer.
MuM, Wim, GleP, Brid, VVP, VRiv, MuF, GipP, OtP, WaP, Gold, CVU, GGr, DunT, NIS, EGL, EGU, WPro, HSF, HNF, OtR, Strz, MonT, HFE, VAlp. All States (including Lord Howe Is.) except WA, NT, Norfolk Is. New Guinea. In swamps and on stream-banks in the southern part of the State (rare in Volcanic Plains), often tolerating considerable shade; the commonest native Cyperus in the State.
