Description from Flora of China
Herbaceous vines, glabrous. Roots tuberous, huge. Branches becoming purplish black, longitudinally striate. Petiole slightly longer or shorter than leaf blade, base geniculate; leaf blade peltate, insertion 3-4 cm from margin, rotund, 10-12.5 cm in diam., thinly papery, base rounded, apex rounded or inconspicuously mucronate, palmately 8-10-veined, often dichotomously branching, fine reticulation clearly seen abaxially. Male inflorescences compound umbelliform cymes, axillary, solitary or many on short axillary branches; peduncle slightly fleshy, slender when dry, 2-4(-5) cm; umbellet pedicel usually less than 1 cm, usually without bracts and bracteoles; flowering pedicels 4-6 mm. Male flowers: sepals 6, submembranous, outer whorl broadly elliptic, ca. 2 × 1.5 mm, base attenuate, inner whorl broadly rhomboidal, ca. 2.1 × 2.1 mm, both glabrous; petals 3, plump, fleshy, 0.8-1 × 1.8-2 mm, with verruculose processes; synandrium with short stipe, ca. equal to petal in height. Female inflorescences and flowers unknown. Drupes not mature, with fleshy stalk, broadly obovate. Fl. summer.
The tuberous rootstock of Stephania officinarum contains large amounts of the alkaloids isocorydine and 1-tetrahydropalmatine.
● Yunnan (Gengma, Lincang).