The Round-leaved dock (Rumex obtusifolius) belongs to Polygonaceae (the Knotweed family). It is native to Europe. It was introduced into Japan in the middle days of Meiji Era (1868-1912). This herb grows along road sides and in disturbed areas, and up tp a height of 50-130 cm. The stems are erect and the leaves are ovate-elliptic to oblong with fine wavy edges. The stems, petioles and mid-rib of leaves are often tinged reddish. The pale green flowers bloom in racemes atop of stems from June to September. The sepals are ovate with spiny edges and the fruits have red fine mottles.