Rhizomatous perennial. Culms 30–90(–120) cm high, 1–3.5 mm diam. Leaves ± erect 2–7 mm wide. Inflorescence a compact head of 3–6 spikelets, or with 1–3 spikelet clusters on branches 1–4 cm long; involucral bracts 4–22 cm long, 1.5–2.5 mm wide. Spikelets 1–2 cm long; glumes yellow-brown, c. 7 mm long, plus awn c. 2 mm long; hypogynous bristles about half as long as nut, usually deciduous; style 2-fid. Nut lenticular with concave faces, broad-obovoid, straw-coloured to dark golden brown, shining, minutely but obviously reticulate, 3.5–4 mm long, 2.5–3 mm diam. Flowers spring–summer.