Japan Flora: Submersed green annual without rhi­zomes; leaves radical, rosulate, thin, long-petioled, oblanceo­late in the vernal, broad-ovate or ovate-cordate in the summer ones, 10-25 cm. long, 2-15 cm. wide, obtuse, 5- to 9-nerved, entire or obscurely dentate; scape elongate, the spathe to 4 cm long, with or without prominent crispate wings; sepals linear-lanceolate, obtuse, green; petals thin, ovate-orbicular, much longer than the sepals, white to reddish; ovary sessile within the spathe. Aug.-Oct. Ponds and paddy fields. 

Honshu, ShilJoku, Kyushu. India and Australia.