Robust, rhizomatous, to 1.5 m high. Female spikes in twos, threes or occasionally fives at each inflorescence-node, red-brown, on often short peduncles. Utricles 3-3.5 mm long, easily punctured, beak minute. Stigmas 2.

Rhizomatous; robust, 50–150 cm. high, bright green. Culms (1.5)–2–3.5–(5) mm. diam., triquetrous, scabrid on the edges; basal sheaths dull brown or red-brown, margins shredding into fibres wrapped round the culm. Lvs ∞, us. much > culms, 3.5–6–(8) mm. wide, double-folded, margins scabrid. Spikes (6)–10–20, pend. on filiform peduncles, or upper spikes erect, sessile; upper 3–6 spikes male, sometimes mixed with female fls, solitary or the lower geminate, 2–4 mm. diam., glumes hardly awned; remaining spikes female, us. with male fls at the top, geminate, ternate or occ. quinate, lowermost spikes (2)–4–7–(9) cm. × (4)–5–7 mm., upper spikes progressively smaller. Glumes (excluding awn) < utricles, narrow-ovate, obtuse, truncate or emarginate with a hispid awn of variable length, red-brown with a light brown, 3-nerved midrib, margins narrow, hyaline. Utricles (2.6)–3–3.5–(3.8) × (1.3)–1.5–2–(2.3) mm., ovoid to oblong, saccate, inflated or unequally compressed, 6–10-nerved on each face, olive green, becoming greenish brown or red-brown, soft, margins glab.; beak very narrow, c. 0.2 mm. long, orifice entire, rarely slightly bidentate. Stigmas 2. Nut c. 1.5 mm. long, in lower half of utricle, biconvex, orbicular-ovoid or obovoid, brown.