Tall, rhizomatous perennial, often forming extensive clumps. Culms ± terete, smooth, glabrous, 1–2.5 m high, 5–10 mm diam., often branching extravaginally at nodes. Leaf-blades to 2.5 m long, 5–20 mm wide; sheaths yellow-brown at base. Inflorescence loose, interrupted-oblong in outline, 18–35 cm long, 6–9 cm diam.; involucral bracts longer than inflorescence. Spikelets often with only the lower flower bisexual, 3–5 mm long; glumes 5 or 6, obtuse to acute, red-brown, glabrous, about 4 lowest empty, shorter than fertile glumes, which are 3.5–4.0 mm long; style 3-fid; style-base inconspicuous at maturity. Nut ellipsoid to ovoid, glabrous, smooth, shining, mid-brown, 2.0–2.5 mm long, 1.3–2 mm diam., with basal disk inconspicuous and often remaining with spikelet. Flowers spring–summer.
GleP, Brid, VVP, GipP, OtP, WaP, EGL, WPro, HSF, OtR. Also WA, SA, Qld, NSW, Vic, Tas (doubtfully naturalised). New Caledonia. Occasional in swampy areas and margins of streams and lakes near the coast, tolerating low to moderate levels of salinity.
