Description from Flora of China
Aristolochia austroyunnanensis S. M. Hwang.
Shrubs climbing. Stems terete to slightly complanate, striate, densely yellow-brown villous. Petiole 2-4 cm, densely yellow-brown villous; leaf blade narrowly ovate, ovate-oblong, or lanceolate-ovate, 12-18 × 5-8 cm, leathery, both surfaces glabrous or villous along veins, veins pinnate, 4-6 pairs, base shallowly cordate, apex acuminate. Racemes on old woody stems, 2- or 3-flowered, 4-6 cm. Pedicel 3-4 cm, pendulous, yellow-brown villous; bractlets ovate-lanceolate, ca. 10 × ca. 5 mm. Calyx yellow with purple-brown blotches and reticulate veins; tube geniculately curved, abaxially densely villous; basal portion of tube 50-65 × 10-20 mm; limb oblong-peltate, 5-8 × 4-7 cm, 3-lobed; lobes unequal, rounded. Anthers oblong, 3-4 mm. Gynostemium 3-lobed. Capsule narrowly ellipsoid, 10-15 × 5-8 cm, dehiscing basipetally. Seeds not seen. Fl. Sep, fr. Dec.
Forests on limestone mountain slopes; 1800-1900 m. Guangxi, S Yunnan [Vietnam].