Description from Flora of China
Herbs twining. Stems 6-angled, glabrous. Petiole 2-4 cm, glabrous; leaf blade ovate-cordate to ovate-triangular, 10-12 × 5-10 cm, leathery, abaxially densely puberulous, hairs on veinlets forming closely foveolate reticulation, adaxially glabrous, veins palmate, 2-3 pairs from base, base cordate, sinus 1-1.5 cm deep, apex acute or acuminate. Racemes in axils of leafy shoots, 3- or 4-flowered, 3-5 cm. Pedicel ascending, ca. 0.8 cm, glabrous; bractlets subulate to lanceolate-ovate, 3-10 × 1-4 mm, base rounded to cuneate. Calyx yellowish green, limb dark purple; tube rectilinear or slightly curved, abaxially glabrous; utricle globose, ca. 3.5 mm in diam., sessile; tube ca. 15 × 2 mm; limb unilateral, ligulate, ovate-oblong, 1-1.5 × ca. 0.5 cm. Anthers elliptic, ca. 0.3 mm. Gynostemium 6-lobed. Capsule cylindric or obovoid, 3-4 × 1.5-2 cm, dehiscing acropetally. Seeds ovoid-triangular, ca. 5 × 5 mm. Fl. Mar-Apr, fr. May-Jul.
This species is used medicinally.
* Thickets, in valleys, rock fissures; 500-700 m. Guangdong, Guangxi.