Buttercup, a name applied to several species of the genus Ranunculus (q.v.), characterized by their deeply-cut leaves and yellow, broadly cup-shaped flowers. Ranunculus acris and R. bulbosus are erect, hairy meadow plants, the latter having the stem swollen at the base, and distinguished also by the furrowed flower-stalks and the often smaller flowers with reflexed, not spreading, sepals. R. repens, common on waste ground, produces long runners by means of which it rapidly covers the ground. The plants are native in the north temperate to arctic zones of the Old World, and have been introduced in America.