The most characteristic members of the order are twining plants with generally smooth heart-shaped leaves and large showy white or purple flowers, as, for instance, the greater bindweed of English hedges, Calystegia sepium, and many species of the genus Ipomaea, the largest of the order, including the "convolvulus major" of gardens, and morning glory.
The large showy flowers are visited by insects for the honey which is secreted by a ring-like disk below the ovary; large Convolvulus sepium, slightly reduced.
Among the nine hundred species of Solanum less than a dozen have this property of forming tubers, but similar growths are formed at the ends of the shoots of the common bramble, of Convolvulus sepium, of Helianthus tuberoses, the so-called Jerusalem artichoke, of Sagittaria, and other plants.