Description from Flora of China
Vines with old branches slightly woody. Branches and leaves containing pale yellow or white juice; branches stout, longitudinally sulcate, glabrous. Petiole stout, usually subequal to or slightly shorter than leaf blade; leaf blade triangular-rounded, length and width 10-16 cm, sometimes smaller, thinly papery, base rounded to subtruncate, margin repand or sparsely horned serrate, apex acutely acuminate or subentire, palmately 10- or 11-veined, with clear papilla on fine reticulation. Male inflorescences compound umbelliform cymes, often several on short axillary branches, leafless and twining; peduncle 3-7 cm; umbellet pedicels 3-5, 2-4.5 cm; cymelets 3-5-flowered; bracteoles narrowly lanceolate; pedicel 1-3 mm. Male flowers: sepals usually 6(or 8), yellowish green, outer whorl spatulate-cuneate, ca. 2.5 mm, inner whorl slightly wider; petals 3(or 4), orangish yellow, 1.5-2 × 2-2.5 mm, one deeply concave; synandrium columnar, ca. 1 mm. Female inflorescences condensed to capitula; peduncle 2.5-5 cm, conspicuously swollen apically. Female flowers zygomorphic; sepal 1, subovate, ca. 0.4 mm; petals 2, fleshy, broadly ovate to conchiform, slightly larger than sepals; fruiting pedicel slightly fleshy. Drupes red, broadly obovoid; endocarp ca. 1 × 0.8 mm, with columnar ornamentation conspicuously curved and hooklike. Fl. Mar-May.
The tuberous rootstock of Stephania hainanensis contains a large amount of the alkaloid rotundine.