The Broad-leaved willowherb (Epilobium montanum) belongs to Onagraceae (the Evening primrose family). It is a perennial herb that is distributed from Tohoku region of Honshu to Hokkaido in Japan, and from temperate regions of Asia to Europe. It grows in moist meadows in the mountains and grows 20 to 80 cm tall. It has long ovate, opposite leaves with sharp serrations on the edges, and produces light red flowers at the top of its stems from July to August. It is similar to the "iwa-akabana", but has four lobed stigma.