Clematis, genus of perennial, chiefly climbing shrubs of the buttercup family (Ranunculaceae) with about 370 species distributed over most of the world, especially in Asia and North America. Many species are cultivated in North America for their attractive flowers. The flowers may be solitary or in large clusters. The many fruits are conspicuous because of their persistent styles; they occur in spherical groups. The leaves are opposite, individually stalked, and compound—i.e., have several parts.
Common species include woodbine (Clematis virginiana); traveler’s joy, or old-man’s-beard (C. vitalba); virgin’s bower (C. cirrhosa); and vine bower (C. viticella). The most popular horticultural hybrids are found primarily in three species: C. florida, flowering on old wood in summer; C. patens, flowering on old wood in spring; and C. jackmanii, flowering on new wood in summer and fall.