Eleocharis japonica Miquel, Ann. Mus. Bot. Lugduno-Batavi 2: 142. 1865; Scirpus japonicus (Miquel) Franchet & Savatier (1877), not (Maximowicz) Fernald (1905).

Culms usually very short, hairlike. Perianth bristles shorter than nutlet, laxly retrorsely spinulose. Nutlet 0.8-0.9 mm; persistent style base usually ± elongate. Fl. and fr. Mar-Oct.

Paddy fields, shallow water margins; 200-1700 m. Anhui, Fujian, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Yunnan, Zhejiang [Japan, Korea, N Thailand].