Isopyrum vaginatum Maximowicz, Fl. Tangut. 18. 1889; Actaea vaginata (Maximowicz) J. Compton; Coptis ospriocarpa Brühl.

Rhizome robust, creeping, 4--9 cm in diam., branched, with fibrous roots. Stems more than 15 cm tall, to 75 cm at fruiting, glabrous or subglabrous, with 2--4 membranous broad scales at base. Cauline leaves ca. 2, glabrous, long petiolate; petiole 5--34 cm; leaf blade triangular, to 24 cm; primary seg-ments ovate to broadly so, central secondary segments ovate-triangular, 4--7.5 × 3.5--6.5 cm, central tertiary segments rhomboid, 1- or 2-pinnatifid, unequally dentate at margin, lateral tertiary segments similar to central tertiary ones, oblique. Raceme 4--6-flowered; bracts ovate, membranous. Pedicel 1.2--1.4 cm. Flowers 1.2--1.4 cm in diam. Sepals 8--11 × 4--7 mm, 3-veined, margin irregularly shallowly wavy at apex, apex rounded. Petals 2.5--5.5 mm, multiveined. Stamens 4--7 mm. Follicles 1 or 2(or 3), 3.5--7 × 0.3--0.7 cm. Seeds 12--16, black when ripe, 3--4 mm. Fl. May--Jun, fr. Jul--Sep. 2n = 16*.

Forests, forest margins, grassy slopes; 2800--4000 m. S Gansu, E Qinghai, S Shaanxi, W Sichuan, SE Xizang, NW Yunnan [Bhutan, India, N Myanmar, Sikkim].