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(Ipomoea purga), an herbaceous perennial twining plant of the family Convolvulaceae. (The plant is sometimes separated into the genus Exogonium.) The thin, creeping rhizome has thickened tuberous roots. The leaves are cordate. The flowers are large, funnelform, and pinkish violet; one to three flowers are borne by each axillary peduncle. The jalap plant is native to the moist mountainous forests of Mexico. It is cultivated as a medicinal plant in Mexico, Central America, the West Indies, and India. The roots contain 8–12 percent resin, almost 95 percent of which consists of the glycoside convolvulin. Preparations made from dried roots are used as a strong laxative.