BINDWEED

plants of the closely related genera Convolvulus and Calystegia, mostly twining, often weedy, and producing handsome white, pink, or blue, funnel-shaped flowers. Bellbine, or greater bindweed (Calystegia sepium), native in Eurasia and North America, bears arrow-shaped leaves and white to pink, 5-centimetre (2-inch) flowers. This twining perennial grows from creeping, underground stems and is common in hedges, woods, and along roadsides. Its range tends to coincide with that of its principal pollinator, the hawkmoth. Sea bindweed (C. soldanella), with fleshy, kidney-shaped leaves and deep pink, 5-cm blooms, creeps along European seaside sand and gravel. Several Convolvulus species are widespread or conspicuous. The weedy, perennial field bindweed (C. arvensis), which is European but widely naturalized in North America, twines around crop plants and along roadsides. It bears long-stalked clusters of fragrant pink, white, or striped blooms, 2 cm across, among arrow-shaped leaves. Scammony, a purgative, is derived from the rhizomes of C. scammonia, a trailing perennial with white to pink flowers, native in western Asia. Rosewood oil comes from certain species of Convolvulus.