Japan Flora: Larger; leaflets obcordate to depressed- obtriangular, 1-2.5 cm. long, 2-4 cm. wide; petals 15-18 mm. long; capsules oblong, 1-1.2 cm. long, or in cleistogamic flowers ovoid and 5-6 mm. long; Apr.-May. Mountain woods.
Honshu, Shikoku, Kyushu; rather common. Formosa, China, and n. India.