Cistus

Cistus (Gr.), or ROCK-ROSE, a genus of thalamifloral dicotyledons, which gives its name to the Cistaceæ, an order allied to Crucifere and Capparideæ, and containing about four genera and sixty species of shrubs and herbs, chiefly Mediterranean. Many species are more or less resinous; and from the twigs of some species of Cistus, natives of southern Europe and the Levant, particularly C. creticus, C. cypricus, and C. ladaniferus, the resinous substance called Ladanum is obtained, which is used as a stimulant, chiefly in plasters, but has become obsolete in modern medical practice. Many species of Cistus are much cultivated for the beauty of their large wild-roselike flowers, which are red, white, lilac, yellow, or frequently of two colours. Most of the larger kinds require in Britain some protection in winter. The common yellow Rock-roses of our dry hillsides are species of Helianthemum, chiefly H. vulgare. Many pretty varieties of this and other species are grown in gardens, especially on rock-work. Several kinds are North American.