Japan Flora: Tuber depressed-globose, bearing a few small lateral tubers; leaves 2, the petiole terete, erect, 15-25 cm. long; leaflets 3, rather thick, ternate, sessile, broadly rhomboidal-ovate, 8-20 cm. long, 4-10 cm. wide, entire, prominently lustrous above, subabruptly narrowed into a filiform tail 5-15 mm. long; peduncle short, 3-10 cm. long; spathe greenish (forma praecox T. Koyama) or uniformly dark purple (forma sieboldii T. Koyama), with a large auricle on each side on the margin of the tubular part, the blade saccate-galeate, the lower half obliquely ascending, the upper half strongly bent forward, 35-4.5 cm. long, short-caudate; spadix-appendage cylindric, the base thickened and abruptly contracted above the florifer­ous part. Mar.-May. Woods near seacoast.

Honshu (Kanto Distr. and westw.), Shikoku, Kyushu. Ryukyus, China, and s. Korea.