Description from Flora of China
Rhizomes stout. Stems with dark purple spots, twining, to 5 mm in diam., terete, striate, internodes 12-20 cm. Petiole (0.5-)1-1.5 cm, slender; leaf blade elliptic to ovate, 7-13 × 2-6 cm, leathery, abaxially slightly green, adaxially green, base rounded, margin crenulate, apex acuminate and caudate, veins 3-5. Cymes many flowered; peduncle 1-13 cm. Pedicel 1-12 cm; bractlets usually present, lanceolate, to 1 cm. Calyx campanulate; tube 1.1-1.5 cm, with a transparent intracalycular membrane at apex; lobes lanceolate, 0.7-1.3 cm × 1-2 mm, apex acute. Corolla purple, campanulate, ca. 5 cm; lobes ovate-triangular, slightly oblique, 5-7 × 5-7 mm, apex acute; plicae semiorbicular to truncate, oblique, ca. 3 mm, margin crenulate. Stamens inserted at middle of corolla tube; filaments subulate, ca. 1.5 cm; anthers narrowly ovoid, ca. 3.5 mm. Nectaries ovate. Style short, ca. 5 mm including linear stigma lobes. Capsules brown, ellipsoid, compressed, ca. 2 cm, included in corolla; gynophore ca. 2 cm. Seeds light brown, discoid, ca. 2 mm in diam. Fl. and fr. Oct-May.
* Forest slopes, scrub, in valleys; 1000-1800 m. W Guangxi, S Yunnan.