直序乌头 zhi xu wu tou

Caudex terete, to 10 cm, ca. 1 cm in diam. Stem 70--120 cm, basally glabrous, apically retrorse pubescent. Middle cauline leaves long petiolate; petiole 4--9 cm, glabrous; leaf blade orbicular-pentagonal, 5--10 × 5--10 cm; central segment rhombic-obovate, 3-fid ± to middle, ultimate lobes narrowly ovate to narrowly linear-lanceolate; lateral segments obliquely flabellate, unequally 2-parted nearly to base. Inflorescence to 60 cm, many flowered, most proximal branches to 15 cm, several flowered; rachis and pedicels densely spreading yellow glandular pubescent and very sparsely white pubescent, or retrorse or ± spreading white pubescent; proximal bracts leaflike, distal ones linear. Pedicels 0.3--3 cm, with 2 bracteoles near middle; bracteoles linear, 3--5 mm. Sepals blue-purple, abaxially yellow glandular pubescent, or retrorse or ± spreading white pubescent; lower sepals ca. 0.8 cm; lateral sepals ca. 1.4 cm; upper sepal navicular or navicular-galeate, 1.6--1.8 cm high, shortly beaked, 1.5--2 cm from base to beak, adaxially glabrous, lower margin slightly concave. Petals glabrous; claw slender; spur subglobose, ca. 1.5 mm; lip ca. 4 mm, slightly concave at apex. Stamens glabrous; filaments 2-denticulate or entire. Carpels 5, densely pubescent. Fl. Aug--Sep.

* Betula forests, scrub, grassy slopes, by streams; 3100--4700 m. E Xizang.