Description from Flora of China
Roots dark brown. Rhizomes light brown, 2-3 mm in diam. Stems sometimes dark purple, twining, terete, striate, internodes 4-13 cm. Leaves sessile or petiole to ca. 3 mm; leaf blade ovate to cordate, sometimes orbicular toward stem base, 3-6(-9) × 1.5-3.5(-4) cm, leathery, sparsely hirsute along veins, base rounded to truncate, apex acuminate and caudate, veins 3-5. Flowers solitary. Pedicel less than 0.5 cm or to 6 cm. Calyx dark purple, campanulate; tube 1.2-1.4 cm, split on 1 side or rarely entire; lobes lanceolate, 3-5 × 1-2 mm, apex acute. Corolla purple, campanulate, 3.5-4(-5) cm; lobes ovate-triangular, ca. 2 × 5 mm, apex acute; plicae truncate, ca. 1.5 × 5 mm, margin crenulate. Stamens inserted at middle of corolla tube; filaments linear-subulate, 1-1.3 cm; anthers ellipsoid, 2-3 mm. Nectaries ovate. Style short, ca. 6 mm including linear stigma lobes. Capsules brown, ellipsoid, compressed, ca. 2.2 cm; gynophore ca. 1.5 cm, slender. Seeds dark brown, discoid, ca. 2 mm in diam., broadly winged. Fl. and fr. Aug-Oct.
* 1700-3900 m. SE Xizang, NW Yunnan