Vines woody. Branchlets terete, densely rusty villous. Leaves opposite, simple; petiole 3-10 mm, sparsely rusty villous; leaf blade ovate-elliptic or narrowly ovate, 7-10 × 2.5-7 cm, papery, sparsely villous and abaxially denser, base subcordate or subrounded, apex abruptly acuminate; primary veins ca. 5 on each side of midrib. Flowers solitary, terminal or axillary, sometimes in 3-flowered terminal cymes; bracts linear, 2-3 mm, along with pedicel and calyx densely villous. Pedicel 2-5 mm. Calyx tube ca. 1.5 mm; lobes 5, filiform, 3-6 mm. Corolla white; tube 1.5-1.8 cm; lobes 1-1.2 cm. Fruit not seen. Fl. Jul.