白线薯 bai xian shu

Deciduous and herbaceous vines. Stems slightly twining, light gray or slightly brown when dry, longitudinally striate, glabrous. Petiole longer than or subequal to leaf blade; leaf blade peltate, insertion 1.5-3 cm from base, triangular or subrounded, 8-18 cm, width subequal to length, thinly papery, both surfaces glabrous or abaxially slightly puberulent along veins, base subtruncate to subrounded, margin undulate to subentire, apex obtuse or sometimes mucronate, palmately 10-veined, raised abaxially, reticulation slender and visible. Inflorescences compound umbelliform cymes, axillary or on short axillary branches with reduced leaves. Male inflorescences slightly slender; peduncle 3-7 cm; umbellet pedicels 5-7, 1.5-3 cm; cymelets slightly dense. Male flowers: pedicel ca. 0.5 mm; sepals 6, outer whorl 1-1.3 mm, inner whorl obovate or broadly obovate, 1.7-2.2 mm, relatively broader; petals 3(or 4), fleshy, very broad, 0.8-1 × 1.5-1.9 mm, margin involute, imbricate; synandrium 0.5-0.7 mm. Female inflorescences condensed to capitula; umbellet pedicel and cymelet pedicel absent when blooming. Female flowers: sepal usually 1, ovate-lanceolate, ca. 1 mm; petals 2, rotund, ca. 0.6 mm. Fruiting pedicel not fleshy. Drupes red, broadly obovate; endocarp 9-10 × ca. 8 mm. Fl. May-Jun, fr. Jun-Aug.

Ravine sides in forests; ca. 1000 m. SE Yunnan [Myanmar].

The tuberous rootstock of Stephania brachyandra contains the alkaloid isocorydine.