Roots carrot-shaped or fusiform-cylindrical, 15-30 × 1-3 cm, often branched. Stems twining, 1-2 m, glabrous, branched; lateral branches 15-30 cm; branchlets 1-5 cm, sterile or fertile. Leaves on main stems and branches alternate, those on branchlets opposite; petiole 0.5-2.5 cm, sparsely shortly setose; blade abaxially gray-green, adaxially green, ovate or narrowly ovate, 1-7.3 × 0.8-5 cm, abaxially sparsely or densely appressed hirsute or villous, rarely glabrous, base subcordate, rounded, or truncate, margin crenulate, apex obtuse or acute. Flowers solitary and terminal on branches, pedicellate. Calyx adnate to ovary up to middle; lobes broadly lanceolate or narrowly oblong, 10-23 × 6-8 mm, margin subentire or sinuate, apex obtuse or acute; sinus between calyx lobes narrow and pointed. Corolla yellow-green, with purple spots inside, broadly campanulate, 1.8-2.3 × 1.8-2.5 cm, shallowly lobed; lobes deltoid, apex acute. Filaments slightly dilated at base, ca. 5 mm; anthers elongate, 5-6 mm. Stigma white setose. Capsule hemispheric at base, conical toward apex, 1-2.4 cm. Seeds numerous, red-brown to dark brown, oblong to ellipsoid, ca. 1 mm, smooth. Fl. and fr. Jul-Oct. 2n = 16.

Forests, thickets, meadows or scrub at forest margins; 900-3900 m. Chongqing, E Gansu, N Guizhou, Hebei, Heilongjiang, Henan, W Hubei, NW Hunan, Jilin, Liaoning, Nei Mongol, Ningxia, E Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, NW Yunnan; one subspecies widely cultivated [Korea, Mongolia, Russia (Far East)].