Any plant of the closely related genera Convolvulus and Calystegia , mostly twining, often weedy, and producing funnel-shaped flowers.
Bellbine, or greater bindweed ( Calystegia sepium ), native in Eurasia and North America, is a twining perennial that grows from creeping, underground stems and is common in hedges and woods and along roadsides. Sea bindweed ( C. soldanella ) creeps along European seaside sand and gravel. Several Convolvulus species are widespread or conspicuous. The weedy perennial field bindweed ( C. arvensis ), European but widely naturalized in North America, twines around crop plants and along roadsides. Scammony, a purgative, is derived from the rhizome s of C. scammonia , a trailing perennial native to western Asia. Rosewood oil comes from certain species of Convolvulus .