Isachne albens var. magna (Merrill) Jansen; I. arisanensis Hayata; I. beneckei Hackel var. magna Merrill; I. magna (Merrill) Merrill; Panicum albens (Trinius) Steudel.

Perennial. Culms erect or decumbent at base, branching and rooting at basal nodes, 30–100 cm tall. Leaf sheaths glabrous or outer margin often ciliate; leaf blades narrowly lanceolate, firm, 7–15 × 0.8–1.8 cm, abaxial surface glabrous, strongly veined, adaxial surface glabrous to hispidulous, margins thickened, apex acuminate; ligule 1–2 mm. Panicle open, effuse, ovate-elliptic or pyramidal in outline, 9–30 cm, eglandular; primary branches smooth or almost so with capillary branchlets; pedicels varying in length. Spikelets elliptic-globose, 1–1.5 mm, whitish green; florets similar, lower floret usually bisexual, upper floret usually female; glumes herbaceous with inflexed scarious margins, 5–7(–9)-veined, usually glabrous, occasionally with a few stiff bristles above middle, obtuse, lower glume equal to spikelet, upper glume slightly shorter; lower lemma very slightly longer than upper, leathery, globose to elliptic-ovate, puberulous or subglabrous, obtuse, upper lemma hairier. Fl. and fr. summer–autumn. 2n = 60.

This widespread species is distinguished by its relatively tall habit and large, eglandular panicle of numerous small, pale spikelets. Specimens of Isachne scabrosa without obvious glands may key out here, but they can be distinguished by their papillose-hispid leaf sheaths.

Rocky mountainsides, streams, forest margins, other moist open places; 500–2600 m. Fujian, Guangdong, Guangxi, Guizhou, Sichuan, Taiwan, Xizang, Yunnan [Bhutan, N India, Indonesia, Myanmar, Nepal, Thailand, Vietnam].