Description from Flora of China
Panicum montanum Roxburgh.
Perennial. Culms scrambling, often rooting at lower nodes, 1–2 m long, branched, terete, glabrous, nodes glabrous to puberulous. Leaves cauline; leaf sheaths striate, puberulous to subglabrous, ciliolate on margins toward throat; leaf blades lanceolate, 5–20 × 1–3 cm, subglabrous to pubescent, cross veins present, margins scabrid, base cordate, apex finely pointed to acuminate; ligule scarcely developed, ca. 0.5 mm, a ciliolate membrane. Panicle broadly ovate in outline, 10–40 cm, much branched; branches slender, spreading, glabrous, smooth or scabrid, bearing spikelets toward the extremities. Spikelets elliptic, 2–2.5 mm, puberulous; lower glume ovate or oblong, 3/4 as long to equaling the spikelet, 3–5-veined, separated by an internode; upper glume as long as spikelet, 3–5-veined; lower lemma similar to upper glume, palea absent; upper floret as long as spikelet, pale yellow or green, smooth, shiny. Fl. and fr. May–Nov. 2n = 36.
Forest margins. Fujian, Guangdong, Guangxi, Taiwan, Xizang, Yunnan [Bhutan, Borneo, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines, Thailand, Vietnam].