Description from Flora of China
Arundinaria armata Gamble, Ann. Roy. Bot. Gard. Calcutta 7: 130. 1896; Oreocalamus armatus (Gamble) T. H. Wen.
Culms 3–5(–10) m tall, 1–3 cm in diam.; internodes terete, 12–14 cm, glabrous, sometimes verrucose; nodes with prominent ridge, nodes at and below mid-culm each with a ring of root thorns; sheath scar with a densely fulvous tomentose ring and persistent culm sheath base. Branches 3 per node. Culm sheaths late deciduous, longer than internodes, papery, densely fulvous setose, margins ciliate; oral setae fulvous; ligule 2–3 mm; blade subulate-triangular, 1–3 cm; leaves 3–5 per ultimate branch; sheath ca. 7 cm, glabrous, veins distinct; auricles weak; oral setae developed; blade narrowly lanceolate, ca. 20 × 1.5 cm, papery to thinly papery, secondary veins 4- or 5-paired. Inflorescence 7–9 cm. Pseudospikelets fasciculate, 5–8 cm, with 3 or 4, gradually larger basal bracts; florets 7–10. Palea subequal to lemma, thinly papery, apex obtuse or slightly bifid. Lodicules transparent, margins white ciliate. Ovary ovoid-ellipsoid; style short, divided close to base; stigmas 2. Fruit unknown.
1300–2000 m. Xizang, Yunnan [India, Myanmar].