Description from Flora of China
Herbs perennial. Rhizomes horizontal. Stems erect, 50-100 cm tall, glabrous, sometimes sparsely hispidulous. Petiole short or nearly absent; leaf blade lanceolate, 7-15 × 1-2 cm, thinly leathery, densely minutely punctate, both surfaces sparsely appressed hispidulous, base cuneate, margin entire, hispidulous, apex acuminate; ocrea tubular, 1.5-2 cm, membranous, appressed hirsute, apex truncate, cilia 1-1.2 cm. Inflorescences terminal, spicate, usually numerous, 6-12 cm; bracts green, funnel-shaped, ciliate, each 3-6-flowered. Flowers dimorphic. Pedicel 2.5-4 mm. Perianth white or pinkish, 5-parted, minutely punctate; tepals elliptic, 2.5-3 mm. Stamens 8, exserted. Styles 2 or 3, connate below middle, included or stamens included and styles exserted on separate plant; stigmas capitate. Achenes included in persistent perianth, black, shiny or opaque, ovoid, trigonous or biconvex, 2.5-3 mm.
Marshy areas, ditches, streamsides, riverbanks; sea level to 1700 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Japan, Korea].