Culms 5–10 m, ca. 2.5 cm in diam., basally nearly straight, apically slightly drooping; internodes ca. 30 cm, basal nodes sometimes with short aerial roots, glabrous; branching to base or 2nd node. Branches 3 to many, clustered on each node; branchlets on lower nodes usually specialized into thorns; central 3 branches dominant. Culm sheaths slightly persistent, ribbed-striate when dry, glabrous, margins ciliate, apex asymmetrically triangular; auricles unequal; larger auricle oblong, ca. 2 × 0.5 cm; smaller auricle obovate to elliptic, ca. 1 × 0.5 cm; oral setae usually absent or 1 or 2 at distal nodes, deciduous, pale yellow or brown-yellow, 5–10 mm, undulate; ligule arched, ca. 2 mm, entire, very shortly white ciliate; blade erect, ovate-triangular to ovate-lanceolate, base nearly 2/3 width of sheath apex, abaxially glabrous, apex subulate, abruptly acuminate. Leaf blade linear-lanceolate to oblong-lanceolate, 8.5–14 × 0.8–1.2 cm, abaxially initially sparsely pilose, adaxially glabrous or subglabrous. Pseudospikelets linear, 4.5–5 cm; basal rachilla very short, glabrous; gemmiferous bracts usually 2, ovate, obtuse; fertile florets 5–12, distal 2 or 3 and sometimes proximal 1 sterile; rachilla segments 2–3 mm, nearly 1/4–1/3 length of palea. Glumes 1, similar to lemma, 5–6(–8) mm, glabrous; lemma navicular, to 1 cm, papery, glabrous, with many pale purple veins, apex acute with fine tip; palea nearly as long as lemma, keels sparsely ciliolate, apex penicillate; lodicules 3, subequal, ovate-lanceolate, margins ciliate, apex obtuse. Anthers yellow, apex obtuse. Ovary hispidulous at apex; style short, slightly thickened, hispidulous; stigmas 3. Fruit unknown.

Forest margins, riversides. S Guangxi [Vietnam].