Saint-John's-wort [sānt jänz′wʉrt]n.any of a genus (Hypericum) of ornamental plants of the Saint-John's-wort family, with usually yellow flowers and numerous stamensadj.designating a family (Guttiferae, order Theales) of dicotyledonous trees, shrubs, and plants used for timber, in drugs, etc.: Also written Saint John's wort
* * *Common name for plants in the family Hypericaceae, which contains 350 species of herbs or low shrubs in eight genera.The family is sometimes considered part of the family Guttiferae. The majority of species (about 300) 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.
* * *▪ plantcommon name for many species in the family Hypericaceae, which contains 9 genera and 560 species of herbs or low shrubs. Members of the family have opposite or whorled, gland-dotted, simple, usually smooth-margined leaves and mostly five-petalled, mainly yellow, flowers with many stamens, which are often united in bundles. The fruits are nearly always dry capsules.About 370 species, both temperate and tropical, belong to the genus Hypericum. Aaron's-beard (H. calycinum; see photograph—>), sometimes known as rose of Sharon, and H. patulum are both shrubby, East Asian species. Aaron's-beard bears pale-yellow flowers with orange stamens, on 30-cm- (1-foot-) tall plants. The shrubby H. patulum has slightly smaller, deep-yellow flowers with darker stamens. H. elatum, from the Canary Islands, has egg-shaped, scarlet fruits. St.-Andrew's-cross (H. hypericoides) is cultivated as an ornamental shrub for its yellow flowers. The genus Cratoxylum, with six tropical Asian species, contains one garden plant, C. polyanthum. It is an aromatic shrub with pink flowers, papery oblong leaves, and winged seeds. H. perforatum has become a serious weed problem in southern Australia and North America; certain beetle species have been introduced in many locations to eat the plants and keep them under control. See also Saint-Andrew's-cross.
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