Description from Flora of China
Plants usually without rhizomes or rarely with short rhizomes. Culms usually decumbent at base and rooting at nodes, 15–50 cm tall, ca. 1 mm thick. Leaf sheaths glabrous, usually shorter than internodes; leaf blades narrowly lanceolate, flat, 2–9.5 × 0.15–0.4 cm, scabrid on both surfaces and margins, apex acuminate; ligule 0.2–0.4 mm, ciliate. Panicle 4–12 cm, narrow; branches one per node, scabrid, with many spikelets near base. Spikelets lanceolate, 2.5–3 mm, purplish gray-green, mottled dark gray; glumes 1.5–2.2 mm, membranous, scabrid, 1-veined, apex acute; lower glume 1.5–2 mm, upper glume 2–2.2 mm; lemma 2.5–3 mm, lower 1/4 of back pubescent, otherwise glabrous or scaberulous; awn 5–9 mm, slender, purplish, scabrid. Anthers ca. 0.6 mm. Fl. and fr. Jun–Nov. 2n = 40.
Moist ground of river banks, around margins of shrubs; 1400–3000 m. Anhui, Beijing, Fujian, Guizhou, Heilongjiang, Henan, Hubei, Shaanxi, Shandong, Sichuan, Yunnan, Zhejiang [Japan].