2n = 100

Rhizome creeping, very stout and woody, 1–1.5 cm. diam. Culms 30–90 cm. × 4–12 mm., in a close-packed, linear series, with internal transverse septa externally distinct at intervals of 1–10 cm., interspersed with septa not visible externally; basal sheaths grey, papery, with an oblique orifice; roots c. 2 mm. diam., red-brown, in a group of up to 5 from the base of each culm. Spikelet (2)–2.5–5–(7) × 0.5–1 cm., cylindrical, with an acute tip. Lowest glume sterile, almost completely surrounding base of spikelet, very short; upper glumes ∞, closely imbricate, 6–8 mm. long, obovate-oblong, obtuse, not keeled but with a strong median nerve and ∞ fine lateral nerves. Hypog. bristles 6–10, us. > nut, with rather large, sparse, retrorse teeth. Stamens 3. Style normally 3-fid, occ. stigmas 2, or all connate to the tip. Nut 2–2.5 mm. long (excluding persistent style-base), orbicular, biconvex, the surface covered with hexagonal reticulations, pale brown, surmounted by the persistent, dark brown, conic, swollen base of the style.