Description from Flora of China
Shrubs climbing. Stems terete, striate-sulcate, villous. Petiole 1-2 cm, sparsely pilose; leaf blade narrowly elliptic to lanceolate-elliptic, 14-25 × 4-6.5 cm, leathery, abaxially sparsely villous along veins, glaucous, adaxially glabrous, veins pinnate, 8-12 pairs, base narrowly auriculate, sinus 0.5-0.7 cm deep, apex acute or acuminate. Flowers axillary, solitary or paired. Peduncle pendulous, 2-3 cm, brown villous; bractlets subulate, minute, inserted on basal 1/3 or peduncle. Calyx yellow-green with purple veins, 7-9 cm; tube geniculately curved, abaxially densely yellow-brown villous; basal portion of tube 30-40 × 6-8 mm; limb discoid-subrotund, 4-6 cm in diam., 3-lobed; lobes broadly rounded, equal. Anthers oblong, ca. 2.5 mm. Gynostemium 3-lobed. Capsule ellipsoid, 5-8 × 1.5-2 cm, dehiscing basipetally. Seeds ovoid-deltoid, ca. 6 × 4 mm. Fl. Apr-Jun, fr. Aug-Oct.
The tuber is used medicinally.
* Thickets, mountain slopes, moist shady valleys; 500-1500 m. Guangdong, Guangxi, Yunnan.