Japan Flora: perianth-segments of the inner whorl ovate-orbicular, slightly cordate at base, rather firm, 5-6 mm. long and as wide, rather prominently netted-veined, the margin with slender hooked spreading spines 2-3 mm. long; achenes gray-brown, lustrous, ovate, acutely 3-angled, 3-3.5 mm. long. May-June. Stream banks and ravines in mountains.
Honshu (Yamashiro Prov.); rare; possibly introduced from China. China to the Himalayas.