Japan Flora: Gla­brous stout rhizomatous perennial; stems 30-60 cm. long, loosely branched in upper part; leaves petioled, narrowly ob­long, 10-20 cm. long, 3-7 cm. wide, abruptly narrowed and acute at both ends, entire or with 1 or 2 teeth in the lower ones, petiolate; flowers 3-5 cm. long; calyx unequally 5-lobed; corolla about 2 cm. long, purplish yellow, 5-lobed; fruit glo­bose, about 1 cm. across, enclosed in the accrescent calyx; seeds reniform, about 2.5 mm. across, reticulate with depressed dots.  Apr.-May. Mountains.

Honshu, Shikoku, Kyushu.