Herbs twining. Stems terete, glabrous. Petiole 2-3.5 cm, glabrous; leaf blade triangular-lanceolate to sagittate, 7-14 × 2-2.5 cm, leathery, abaxially puberulous, hairs along veins forming closely foveolate reticulation, adaxially glabrous, veins palmate, 5-7 pairs from base, base auriculate, sinus 1-1.5 cm deep, lateral lobes parallel or spreading, apex narrowly acuminate. Racemes in axils of leafy shoots, 3- or 4-flowered or flowers almost fascicled, 2-3 cm. Pedicel ascending, 1-1.5 cm; bractlets ovate or lanceolate, 10-12 × 3-5 mm. Calyx dark purple; tube rectilinear, abaxially glabrous; utricle globose, ca. 6 mm in diam., sessile; tube ca. 10 × 2.5 mm; limb unilateral, ligulate, ovate-lanceolate, 0.8-1.2 × ca. 1 cm. Anthers elliptic, ca. 1 mm. Gynostemium 6-lobed. Capsule cylindric to obovoid, 2-2.5 × ca. 1.5 cm, dehiscing acropetally. Seeds ovoid-deltoid, ca. 5 × 4 mm. Fl. Apr-Jun, fr. Jul-Oct.

* Thickets on mountain slopes; 400-600 m. Fujian, Guangdong, Guangxi, Hainan.