Homalocenchrus japonicus Makino ex Honda, Bot. Mag. (Tokyo) 39: 37. 1925; Leersia sinensis K. S. Hao.

Perennial, loosely tufted. Culms decumbent, rooting at lower nodes, upper part geniculately ascending, 60–80 cm tall, nodes densely retrorsely hispid. Leaf sheaths shorter than internodes, scabrid; leaf blades flat, 6–15 × 0.4–0.8 cm, scabrid or abaxial surface smooth, base contracted, apex sharply acute; ligule 2–3 mm, truncate. Panicle elliptic to ovate in outline, 9–12 cm, exserted; branches inserted singly, stiffly ascending or spreading, 4–7 cm, unbranched, thick, slightly flattened, smooth, clothed to near base with approximate or slightly overlapping spikelets. Spikelets lanceolate-oblong, 4.5–6 mm, pale green tinged brownish red; lemma pectinate-hispid on keel only, surface smooth, margins minutely spinulose, apex contracted into a narrowly obtuse beak. Stamens 6, anthers 2.5–3 mm. Fl. and fr. summer and autumn. 2n = 96.

Ponds, flooded fields, wet streamsides, ditch banks, lake shores. Anhui, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Shaanxi, Shandong, Sichuan, Yunnan, Zhejiang [Japan, S Korea].