GARDENIA, in botany, a genus of plants of the madder family (Rubiaceae), containing about 8o species of evergreen trees and shrubs, natives of the warmer parts of the Old World. Several are grown in stoves or greenhouses for their handsome, sweet-scented white flowers. The flowers are developed singly at the end of a branch or in the leaf-axils, and are funnel- or salver shaped with a long tube. The double forms of Gardenia florida (China), known as Cape-jasmine, and G. radicans (Japan) are amongst the most beautiful and highly perfumed of any in culti vation. Gardenias are readily propagated by cuttings. They re quire plenty of heat and moisture in the growing season, and must be kept free from insects such as green fly, red spider and scale-insect.