26. Stephania officinarum H. S. Lo & M. Yang, Guihaia. 8: 310. 1988.
药用地不容 yao yong di bu rong
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.
● Yunnan (Gengma, Lincang).
The tuberous rootstock of Stephania officinarum contains large amounts of the alkaloids isocorydine and 1-tetrahydropalmatine.