Deciduous, densely tufted bamboo; culms solid or with a small cavity, 6-15 m high, 2.5-7.5 cm in diameter but varying according to climate; nodes ± swollen and in open situations bearing leafy, often deflexed branches even from the base, lower nodes often rooting; internodes 30-45 cm long. Culm sheaths variable, the lower shorter than the upper, 8-30 cm long, covered on the back with stiff golden-brown hairs, sometimes glabrous in dry localities, striate, rounded at the tip, ciliate on the margins, very slightly auricled; imperfect blade triangular, subulate, hairy on both sides. Leaf-blades linear-lanceolate, varying from 2.5-5 cm long in dry localities to 25 cm long in moist ones, and 0.5-3 cm wide, rounded abruptly at the base into a short petiole, gradually narrowed upwards into a sharply acuminate, twisted point, rough and often hairy above, softly hairy beneath, scabrid on the margins. Inflorescence a panicle of large dense globular heads, 3-5 cm apart. Spike-lets spiny, usually hairy, the fertile intermixed with many smaller sterile ones, 75-12 mm long, 2.5-5 mm wide, with 2-3 fertile florets; bracts and glumes similar, ovate, spiny; lemma ovate, tipped with a sharp spine surrounded by tufts of hair; palea ovate or obovate, emarginate. Caryopsis brown, shining, ovoid to sub-globose, about 8 mm long, hairy above, beaked with the persistent base of the style; pericarp coriaceous.