Japan Flora: Scandent glabrous perennial from stout creeping elongate rhizomes; young branches dark purple, soon glaucescent; stems slender, 30-100 cm. long, branching; leaves petiolate, narrowly ovate-deltoid, obtuse, cordate, 4-7 cm. long, 2-5 cm. wide, the petioles 8-20 mm. long; flowers solitary in axils, the pedicels 2- 4 cm. long, the calyx-tube yellowish green, slender, slightly recurved above, inflated and globose at base, the limb obliquely truncate, narrowly deltoid-acuminate, slightly recurved on margin, brown-purple inside; capsules globose, about 1.5 cm. long. June-Aug. Thickets and meadows in lowlands;

Honshu (Kanto Distr. and westw.), Shikoku, Kyushu. China.