Herb, dioecious, perennial, rhizomatous, forming dense or diffuse patches to 3 m or more across. Rhizome elongated, 2.5–10.0 mm diam.; scales brown. Cataphylls imbricate, appressed, 4–18 mm long. Culms terete, unbranched, rugose, 40–100 cm long, 1.2–3.0 mm diam.; internodes several, up to 10.5 cm long. Sheaths oblanceolate, brown, scarious, ribbed, often with a short, white tuft of hairs at the acute apex, lax, 12–35 mm long; lamina absent. Inflorescence terminal, erect, narrow, 2–6 cm long, with 4–8 spikelets, rarely fewer; spikelets terminal on filiform pedicels, erect; spathes broad-lanceolate to oblanceolate, acute to obtuse, lax, 1.5–3.0 cm long, 4–7 mm wide, often longer than the spikelets and embracing them, glabrous, outer surface finely rugose and dotted with dark cells. Male spikelets globoid to ovoid, 5.5–7.0 mm long, 5.0–6.5 mm wide; lower 1–3 glumes sterile, upper 30–60 glumes fertile, ovate, caudate, 2.5–3.0 mm long, light-to red-brown, margin shortly hairy; awn 1.2–1.7 mm long. Female spikelets ovoid, 7.0–10.5 mm long, 4.5–7.5 mm wide; lower 2–5 glumes sterile, upper 30–45 glumes fertile, broad-ovate, caudate, 1.9–4.0 mm long, golden-to red-brown, margin usually finely hairy; awn 1.6–2.7 mm long. Male flowers: tepals 6, elliptic to oblong, glabrous; outer tepals slightly longer than inner, 1.9–2.5 mm long; filaments 2.4–3.2 mm long; anthers exserted, 1.2–1.5 mm long. Female flowers: tepals 4, more ovate than males; inner tepals slightly longer, 1.5–2.5 mm long; styles 2, very shortly united at base, recurved. Capsule globoid, 1.0–1.7 mm long. Seeds ellipsoid, brown, smooth, c. 0.8 mm long. Culm anatomy: epidermis with deeply sunken stomates, chlorenchyma of elongated peg cells, not interrupted by thick-walled cells, parenchyma sheath mostly two cells thick, central cavity present.