Culms to 10 m, ca. 3.5 cm in diam.; internodes to 35 cm or more, thinly white powdery; wall 4.5–5 mm thick; nodal ridges weakly elevated, as prominent as sheath scar; sheath scar initially densely retrorsely yellow pubescent on margin. Culm sheaths green or pale green, unmarked or large sheaths with distal sparse small spots, basal sheaths often with purple or golden stripes, distal margins red-purple, base densely fringed with yellow pubescence; auricles and oral setae absent; ligule dark purple, truncate or more commonly weakly concave, less than 1 mm, with red-purple bristles much longer than 1 mm, ciliolate; blade horizontal or reflexed, green-purple, linear, flat, much narrower than ligule at base. Leaves 1 or 2 per ultimate branch; auricles absent or small in young culms; oral setae erect or radiate in young culms; ligule slightly exserted, purple, ciliate; blade lanceolate, oblong to linear, 6–17 × 1.2–2.2 cm, abaxially scabrid along midrib. Flowering branchlets spicate, ca. 5 cm, subtended by 4 or 5 scaly bracts gradually larger; spathes 5 or 6, auricles and oral setae absent or oral setae weakly developed; blade lanceolate to subulate, small. Pseudospikelets (1 or)2–4 per spathe, if 3 or 4 then 1 or 2 smaller and sterile. Spikelets with 1–4 florets. Rachilla glabrous or pubescent; palea shorter than lemma, pubescent; lodicules narrowly rhomboid, ca. 4 mm. Anthers 0.8–4 cm. Stigmas 3. New shoots early May, fl. May.