Japan Flora: Similar to O. griffithii but larger; rhizomes thickened above with densely imbricate scales; leaves long-petioled, the leaflets obtriangular, about 2.5 cm. long, 4 cm. wide, truncate and retuse at apex; scapes bractcate on upper part; sepals oblong, longer than the filaments; capsules lanceolate-cylindric, acuminate, about 2 cm. long. Mountain woods.