黔川乌头 qian chuan wu tou

Rhizome terete, to 12 cm in diam. Stem ca. 40 cm tall, shortly 1-branched below inflorescence, glabrous. Basal leaves ca. 3, long petiolate; petiole 12--24 cm, glabrous, base sheathed; leaf blade pentagonal, 4.8--1.2 × 6--15 cm, both surfaces glabrous, base subtruncate or truncate-cordate, apex acute or long acuminate, 3-parted; central lobe narrowly rhombic, 3-lobed; lateral lobes obliquely rhombic, unequally 2-fid beyond middle. Cauline leaves 1--4, similar to basal ones, or cauline leaves 6--11 and crowded below inflorescence. Inflorescence ca. 20 cm, sparsely ca. 20-flowered, basal bracts subspatulate, distal part 2-denticulate, others linear-lanceolate to lanceolate-triangular; rachis and pedicels appressed or ± spreading yellow puberulous. Pedicel 1--4.2 cm, with 2 bracteoles at base; bracteoles narrowly ovate, 8--11 mm. Sepals purple, abaxially sparsely puberulous; lower sepals ca. 0. 7 mm; lateral sepals ca. 0.9 cm; upper sepal cylindric, 1.6--2 cm high, middle 3--5 mm in diam., external margin erect, lower margin 1.1--1.5 cm. Petals ca. 9 mm; claw upper part and limb sparsely pubescent; lip linear, conspicuous; spur rarely incurved, slightly longer than limb, glabrous. Stamens glabrous; filaments entire. Carpels 3; ovary sparsely appressed pubescent. Fl. May.

* Wet places on mountains, by streams, forests; 1400--2200 m. Guizhou, Hunan, N and W Sichuan.