Plants perennial, densely tufted. Rhizome thick. Stems terete, 25--65 cm × 0.8--1.7 mm, striate; pith continuous. Cataphylls closely embracing stem, reddish brown to brown, sheathlike, 1--9.5 cm; leaf blade absent. Inflorescences pseudolateral, densely to laxly many flowered; involucral bract erect, seemingly a continuation of stem, 5--15 cm. Bracteoles 2, triangular-ovate. Perianth segments greenish, ovate-lanceolate, 2--3 × ca. 0.9 mm, equal, apex acute. Stamens 3; filament longer than anther; anthers 0.8--0.9 mm. Ovary 1-loculed, incompletely 3-septate; placentation parietal, a semilunar valve. Capsule globose to ovoid, often longer than perianth, 3-septate, apex retuse to obtuse. Seeds brown, obliquely ovoid, 0.5--0.7 mm, reticulate. Fl. Apr--Jul, fr. Jun--Sep.

Forests, wet land under forests, shaded and wet places on mountain slopes, near ravines, open hillsides, streamsides, trail sides, roadsides; 300--1800 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shandong, Shanxi, Sichuan, Xizang, Yunnan, Zhejiang [Japan, Korea].