Saint-John's-wort

Common name for plants in the family Hypericaceae, which contains 560 species of herbs or low shrubs in eight genera. The family is sometimes considered part of the family Guttiferae. The majority of species (about 370) belong to the genus Hypericum. Their leaves are opposite or whorled, dotted with glands, and usually have smooth margins. Several species are cultivated in temperate regions for their handsome flowers. H. perforatum, a showy golden flower grown in both the Old and New Worlds whose buds contain a red oil, has long been credited with magical and medicinal powers; today it is being widely used and studied for its possible efficacy against depression.