Rhizome ascending, cylindric, elongate, 1--2 cm thick, with some scattered roots. Leaves fasciculate, basally gradually narrowed into a long petiole; leaf blade narrowly oblong-lanceolate to lanceolate, 45--55 × 2--5 cm, glabrous, turning blackish when dry. Scape erect, 50--80 cm. Raceme sometimes many branched and paniculate; bracts small. Flowers usually paired, rarely solitary or in clusters of 3; pedicel 3--5 mm, articulate near middle. Tepals white, elliptic-oblong, 8--10 × 3--4 mm. Stamens shorter than tepals; anthers 3--4 mm, slightly longer than filaments. Capsule subglobose, 6--7 × 7--9 mm; seeds ca. 4 per valve. Fl. and fr. Apr--May.

Forests, thickets, hillsides along valleys; 400--1500 m. Guangxi, S Yunnan [Laos, Malaysia, Thailand, Vietnam].