Perennial, 30-70cm tall. Wet places along rivers in lowlands, by water. Korea, Japan, China, Mongolia, Russia. Stems usually simple, rarely branched at base, proximally glabrous. Leaf blade lanceolate to narrowly so, lengths 3-11cm, widths 1cm, glabrous, margin serrulate, apex acuminate. Flowers yellowish, Jul. Capsule red-purple, seeds ovoid-oblong, tuberculate.