Japan Flora: The cultivated selections often have double flowers with larger often spreading inner perianth-segments.

Var. spontanea (Makino) Nakai. Rhizomes branched, brown-fibrous; leaves 20-60 cm. long, 5-12 mm. wide, the midrib prominent; scapes 40-80 cm. long, unbranched, few- bracteate and -flowered, die uppermost bract green, linear- lanceolate, acuminate, 5-8 cm. long, the pedicels 3-5 cm. long; flowers red-purple, about 10 cm. across, the outer perianth-segments elliptic, clawed, the limb yellow at base, the inner segments smaller, erect; anthers yellow, the stigma-appendages subentire. June-July.

Hokkaido, Honshu, Kyushu.