Culms 5–20 m tall, 1.2–4.0 cm in diameter; young culms glaucous, with a white waxy ring below each node; internodes 1–25 cm long, with walls thin, 2.5–3.0(−5.0) mm thick (mid-culm portion). Branches developing from the lower quarter or from around the mid-culm upwards. Culm leaves 8–13 cm long ×10–15 cm wide, at top shallowly convex to truncate, on back covered with thick white wax and appressed black hairs; blades narrowly triangular, erect, slightly inflated at base, often slightly wavy, 9–20 cm long, 4.5–6.0 cm wide near the base; auricles small lobes, 0.5–1.0 mm tall, fragile, bearing curved fimbriae; ligules 0.5–1.0 mm tall, with margin irregularly denticulate. Leaves 5–9 per branchlet; blade 15–30 cm long × 2–5 cm wide, glabrous, occasionally sparsely hairy near the base, rounded to acute or attenuate at base, acuminate at apex; pseudo-petiole 0.2–0.5 cm long; leaf sheaths 3–6 cm long, puberulous, with hairy margins; auricles tiny falcate lobes, with margins fringed with bristles up to 1 cm long, sometimes absent; ligules ca 0.5 mm high, irregularly toothed along margin. Pseudo-spikelets 1.5–2.5 cm long; subtending bract chartaceous, ca 4 mm long, sparsely hairy on back. Spikelets 0.5–1.2 cm long; glume 1, chartaceous, 3–4 mm long, mucronate, with ciliate margins, 5–7-nerved; lemmas similar to glume, 4–5 mm long; paleas chartaceous, 4–5 mm long, 2-keeled, keels ciliate, 2-nerved between keels and 3-nerved on each involute margin; lodicules membranaceous, 3(4–5), ciliate. Anthers 3.0–3.5 mm long; filaments free; anther apices mucronate (the connective prolonged beyond the anther apex), glabrous. Fruits compressed globose, 4–5 mm.