Hypericum perforatum, commonly known as St John's wort, is a flowering plant in the family Hypericaceae and the type species of the genus Hypericum. It is a perennial that grows up to one metre tall, with many yellow flowers that have conspicuous black glands around their edges, long stamens, and three pistils. Probably a hybrid between close relatives H. attenuatum and H. maculatum that originated in Siberia, the species now has a cosmopolitan distribution. It is native to temperate regions across Eurasia and North Africa, and has been introduced to East Asia, Australia, New Zealand, and parts of North and South America. In many areas where it is not native, H. perforatum is considered a noxious weed. It densely covers open areas to the exclusion of native plants, and is poor grazing material. As such, methods for biocontrol have been introduced in an attempt to slow or reverse the spread of the species.
Hypericum is a genus of flowering plants in the family Hypericaceae. 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 TriadenumRaf.
Hypericum androsaemum, the shrubby St. John's wort, is a flowering plant in the family Hypericaceae. Commonly called tutsan or sweet-amber, the species is cultivated as an ornamental plant because of its striking red-tinted foliage, bright yellow petals, and its large clusters of fruit. Cultivars like 'Albury Purple' and 'Golden Tutsan' which have leaves with more pronounced purple and golden coloring, respectively.
Hypericum olympicum, commonly known as the Mount Olympus St. John's wort, is a species of flowering plant in the family Hypericaceae found in the Balkans and Turkey and introduced to western Europe. It has been widely cultivated for centuries because of its large, showy flowers, which are far larger than those of most other species in Hypericum.
Hypericum aegypticum is a species of flowering plant of the St. John's wort family (Hypericaceae) which is native to the Eastern Mediterranean. It was described by Carl Linnaeus in the second volume of his Species Plantarum in 1753, who named it after Egypt despite it not being distributed there. The plant is commonly known as shrubby St. John's wort or Egyptian St. John's wort in English. Like other members of section Adenotrias, it is found among limestone rocks in coastal areas. While it has been evaluated as threatened on the island of Malta, the species has no legal protections.
Hypericum sinaicum is a perennial herb in the genus Hypericum, in the section Adenosepalum.
Hypericum undulatum, the wavy St Johns Wort, is a herbaceous perennial flowering plant native to western Europe and northern Africa. The specific name undulatum is Latin, meaning "wavy" or "undulated", referring, just as the common name, to the wavy leaf margins of the herb. The plant has a diploid number of 16 or 32.
Hypericum japonicum, known as matted St. John's-wort, is an annual herbaceous flowering plant in the St. John's wort family Hypericaceae, in Hypericum sect. Trigynobrathys.
Hypericum sechmenii, commonly called seçmen kantaronu in Turkish which means Seçmen's St. John's wort in English, is a rare species of flowering plant of the St. John's wort family (Hypericaceae) that is found only in the Eskişehir Province of central Turkey. It was described by Turkish botanists Atila Ocak and Onur Koyuncu who named the species in honor of Özcan Seçmen, a fellow Turkish botanist. Found in the crevices of exposed limestone, it is a perennial herb which grows in clusters of stems 3–6 centimetres tall and blooms June to July with bright yellow five-petalled flowers. Formally described in 2009, the species was first collected in 2006 and has since been found in only two localities with an estimated population of less than 250.
Hypericum formosissimum is a species of flowering plant in the family Hypericaceae, section Adenosepalum, in the Hypericum huber-morathii group.
Hypericum virginicum, the marsh St. Johns-wort or Virginia marsh St. Johnswort, is a species of flowering plant in the family Hypericaceae. It is native to the central and eastern United States and eastern Canada.
Hypericum coris, the heath-leaved St. John's wort, also called yellow coris, is a species of flowering plant in the family Hypericaceae, and is the type species of sect. Coridium. It is a low shrub, and it is found in Switzerland and northwestern Italy. The species has been a popular garden plant since the 18th century, valued for its long flowering period and for how well it adapts to cultivation.
Hypericum antiquum is an extinct species of the genus Hypericum that was present during the Eocene epoch. The species' fossils are the oldest collected of Hypericum, and it is believed that the species is the common ancestor of the tribe Hypericeae. Fossil seeds have been found in Russia, and the predicted paleoregion of the species stretched across Eurasia. It is theorized that one factor leading to the species' extinction is a global cooling at the end of the Eocene that removed much of its habitat.
Hypericum tubulosum, the lesser marsh St. Johnswort or southern marsh St. John's-wort, is a species of flowering plant in the family Hypericaceae. Formerly classified as synonym Triadenum tubulosum, the species is found across the Southern United States and Midwest. It grows in wetlands such as bogs and floodplains.
Hypericum heterophyllum is a flowering plant in the Hypericaceae family and is the only species in Hypericum sect. Heterophylla.
Hypericum holyi is an extinct species of the genus Hypericum that was present from the Lower Miocene to the Upper Miocene. Fossil seeds of the species have been found in Central Europe in general and Central Jutland, Denmark, in particular.
Hypericum septestum is an extinct species of the genus Hypericum that was present during the Oligocene and Miocene epochs. Its holotype is a fossil seed from the Lower Oligocene that was collected in Western Siberia in 1965, and fossils of the species has also been found in other parts of Russia and in the Czech Republic.
Hypericum tertiaerum is an extinct species of the genus Hypericum. Seeds of H. tertiaerum have been found in Central and Eastern Europe and Siberia, and date from the Lower to Upper Miocene and the Pliocene. While it has sufficient identifying characteristics to place it within Hypericum, there is not enough surviving detail to assign it to any subdivisions within the genus. However, it has been determined that the seeds of H. japonicum, H. virginicum, and H. tubulosum closely resemble those of H. tertiaerum.
Hypericum miocenicum is an extinct species of the genus Hypericum. Seeds of the species have been recorded from the Late Oligocene in Germany, the Late Miocene in Poland (Poznan), and the Pliocene in Germany (Thuringia). It differs from H. septestum, a more frequently found Hypericum paleospecies, by its thinner foveole walls and the shape of its surface cells, which are more rectangular.
