Japan Flora: Shrub with gray-brown branches, glabrous or often loosely pilose while young; leaves ovate-elliptic, ovate-oblong, or obovate, sometimes ovate, 6-10 cm long, 2.5-5 cm. wide, acuminate, acute at base, short-toothed, nearly glabrous above, densely whitish short-pubescent beneath, the petioles 4-8 mm. long; flowers 2 or 3 in upper leaf-axils, often short-pedunculate; ovary glabrous or scattered pilose; caljTC-segments lanceolate-linear, 3-7 mm. long, slightly pilose; corolla reddish, 3-3.5 cm. long, glabrous or nearly so externally, gradually ampliate; style subexserted. May- June.

Hokkaido, Honshu. 

f. albiflora (Siebold & Zucc.) Rehder. Flowers white.