Ascyrum

Hypericum is a genus of flowering plants in the family Hypericaceae (formerly considered a subfamily of Clusiaceae). The genus has a nearly worldwide distribution, missing only from tropical lowlands, deserts and polar regions. Many Hypericum species are regarded as invasive species and noxious weeds. All members of the genus may be referred to as St. John's wort, and some are known as goatweed. The white or pink flowered marsh St. John's worts of North America and eastern Asia are generally accepted as belonging to the separate genus Triadenum Raf.

Hypericum is unusual for a genus of its size because a worldwide taxonomic monograph was produced for it by Norman Robson (working at the Natural History Museum, London). Robson recognizes 36 sections within Hypericum.