Japan Flora: Leaves long-petioled, ovate-hastate or hastate, 9-12 cm. long, 6.5-8 cm. wide, acute, lustrous, glabrous beneath; perianth tubular-globose, about 2 cm. long and as wide, sub truncate at base, with 15 longitudinal ribs and accompanying transverse veinlets inside, the lobes spreading, broadly ovate, about 12 mm. long, 14 mm. wide. Apr.-May.