Japan Flora: Rhizomes long-creeping; stems elongate, branched; leaves ovate, deltoid-ovate to elliptic, 5-10 cm. long, 2.5-7 cm. wide, acuminate, deeply cordate, the margins somewhat uneven, entire or shallowly lobed, glabrous; inflorescence spicate; flowers sessile with spreading tepals, the staminate erect, often branched, the pistillate loosely arranged; stigma 3-fid, entire; capsules depressed ovate-orbicular; seeds wing-margined. May-June.

Honshu, Shikoku, Kyushu.