Herbs, dioecious, perennial, rhizomatous, forming dense or diffuse patches to 1 m or more across. Cluster roots present. Rhizome horizontal, up to 1 cm diam.; scales brown. Culms terete, smooth, 0.5–2 m long, 3–5 mm diam., bright green, bearing in the upper portion dense clusters of repeatedly branched, filiform, sterile, lateral branches; internodes numerous. Sheaths closely appressed, tan, 1.5–3.0 cm long. Inflorescence narrow, of 15–450 spikelets on filiform branches; male and female flowers on a short stipe 0.2–0.5 mm long, shortly adnate to the subtending glume and dispersed with the glume. Male spikelets ovoid to globular, 2.5–7.0 mm long; fertile glumes c. 1–4 mm long, ovate, awned. Female spikelets ellipsoid to shortly cylindrical, 3.5–10 mm long, apex often acute; fertile glumes 2.5–6 mm long, ovate to acuminate, aristate. Male flowers: tepals 6, oblong to elliptic, acute to mucronate, glabrous, equal in length, 1.2–2 mm long; filaments 1.5–2.4 mm long; anthers exserted, 0.5–1.3 mm long. Female flowers: tepals 4, oblong to ovate, mucronate to obtuse, 1.4–2.6 mm long; styles 2, very shortly united at base, recurved. Capsule dispersed with the glume, late-dehiscent, compressed, circular or elliptical in outline, 0.8–1 mm long. Seed ellipsoid or more elongated, c. 0.9 mm long, brown, smooth or with convex surface cells. Culm anatomy: chlorenchyma of elongated peg cells, not interrupted by thick-walled cells, central cavity present.
Home