Japan Flora: Stoloniferous; stems erect, 30-70 cm. long, rather slender, usually simple, sometimes branched, glabrous except for thin white hairs on the nodes; lower and median leaves rather thick, broadly lanceolate, 4-8 cm. long, 5-15 mm. wide, acuminate, rounded, obtuse, or auriculately rounded at base, deeply acute-toothed, glabrous, the petioles very short, about 1 mm. long, the upper leaves narrowly lanceolate to broadly linear, 1.5-3 cm. long, 1.5-5 mm. wide, sometimes entire; flowers few, about 5 mm. long, white; calyx about 4 mm. long, 4-lobed, the teeth deltoid- lanceolate, spine-tipped; nutlets about 1.5 mm. long, obovate- cuneate, truncate-rounded at apex. Aug.-Oct. Wet places.

Hokkaido, Honshu, Shikoku, Kyushu. Korea, Manchuria, and e. Siberia.