Japan Flora: Prostrate evergreen shrub, the branches thick, minutely puberulent while young or nearly glabrous, the bud-scales persistent; leaves thick-coriaceous, glabrous, deep green, slightly paler beneath, obovate-oblong, obovate, or oblong, 3-4 (-6.5) cm. long, 15-2 (-2.5) cm. wide, rounded to very obtuse, slightly cuneate and acute to obtuse at base，veinlets impressed above, the petioles 1-1.5 cm. long; inflorescence 3- to 10-flowered, sessile, terminal, the pedicels 2.5-5 cm. long, brown-pubescent; calyx very small; corolla 2.5-35 cm. across, pale greenish yellow, glabrous; stamens 10, puberulous toward the base of filaments; ovary brown-pubescent; style 15-2 cm. long, glabrous, longer than the stamens; capsules narrowly oblong, 1-1.5 cm. long. July-Aug. Alpine slopes;

Hokkaido, Honshu (centr. and n. distr.); rare. n. Korea, Kuriles, Sakhalin, Kamchatka, and e. Siberia.

f. senanense (Yabe) Hara. The stamens petaloid. Honshu (centr. and n. distr.).