Japan Flora: Leaves suberect, green, 5-15 mm. wide, smooth; scapes erect, slender, 50-100 cm. long; inflorescence simple or forked, rather loosely 3- to 15-flowered, the lower bracts linear-lanceolate, those above ovate-caudate, the pedicels 2-15 mm. long; flowers nocturnal, lemon-yellow, fragrant, the perianth-tube 2-4.5 cm. long, the inner segments obtuse, about 7-8 cm. long, 18-25 mm. wide, cross-veins few. July-Aug. Mountains.