Japan Flora: Tuberous root depressed-globose, 5-8 cm. across; stems elongate, branched; leaves alternate, long-petiolate, depressed-cordate or deltoid, glabrous, abruptly acuminate, entire, with bulbils in the axils; staminate spikes 1- to 3-nate, in leaf axils, short-pedunculate, rather densely many-flowered; flowers sessile, the tepals linear-lanceolate, ascending, rather thick, 2.5-3 mm. long; stamens 6. Aug-Sept.

Honshu (Chugoku Distr.), Shikoku, Kyushu.

f. domestica (Makino) Makino & Nemoto. Cultivated for the edible bulbils and tuberous roots.
f. spontanea (Makino) Makino & Nemoto, A wild phase with bitter, non edible bulbils and tuberous roots.