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 grandifolium, the large-leaved St John's wort, is a species of flowering plant in the family Hypericaceae. The plant is a bushy shrub that can grow to almost 2 meters tall. It has large leaves, golden yellow petals, and seed capsules that split open. H. grandifolium is native to the Canary Islands and Madeira in Macaronesia, but has become invasive in other regions, including California, after escaping from cultivation as an ornamental plant. It is parasitized by wasps and fungi, and is capable of reproducing through its rhizomes.
Hypericum bupleuroides is a species of perennial flowering plant in the St John's wort family, Hypericaceae. It grows 45–80 centimeters tall, and notably has perfoliate leaves that are fused at the stem. It has pyramid-shaped flower clusters of 1 to 25 flowers with yellow petals in a star-shaped arrangement. The species is found along the Black Sea coast near the Turkish–Georgian border. Hypericum bupleuroides has a small distribution and specific habitat requirements that make it vulnerable to environmental pressures.
Hypericum hircinum is a species of perennial flowering plant in the St John's wort family, Hypericaceae. It is known as goat St John's wort and stinking tutsan; both names refer to the plant's distinctive odor. The species is a bushy shrub that can grow up to 1.5 meters tall, is many-stemmed, and has golden yellow flowers with conspicuous stamens. The plant has been well-documented in botanical literature, with mentions dating back to at least 1627. Carl Linnaeus described H. hircinum several times, including in his 1753 Species Plantarum which established its binomial. At one point the plant was placed into the defunct genus Androsaemum, but it was returned to Hypericum by Norman Robson in 1985.
Androsaemum, commonly called tutsan, is a section of flowering plants in the family Hypericaceae. It is made up of Hypericum androsaemum, H. foliosum, H. grandifolium, and H. hircinum, as well as the hybrid H. × inodorum. When it was first described, it was considered its own independent genus, but was later placed under Hypericum and demoted to a section. It is also the namesake of an "Androsaemum-group" of related taxa that includes several other sections of Old World species. The Latin name Androsaemum comes from a Greek work to describe plants with red sap, and literally means "blood-man".
Hypericum foliosum, the shining St John's wort, is a species of flowering plant in the family Hypericaceae. It is a bushy shrub endemic to the Portuguese Azores Islands with golden yellow petals and many stems. The species was described by William Aiton in 1789 and was later placed into section Androsaemum of the genus Hypericum by Norman Robson in 1984. It has a diverse essential oil profile made up mostly of monoterpene hydrocarbons, and significant concentrations of various medicinally useful phenols and carotenoids. Populations of the plant are small in number, but quick to colonize cleared areas like groves, landslide areas, and volcanic ash deposits. It is parasitized by fungus and by moth species, but is not considered endangered by the IUCN. H. foliosum is used in traditional medicine on the Azores for diuretic, hepatoprotective, and antihypertensive purposes. It also has in vitro antibiotic and antioxidizing capabilities.
Adenotrias is a section of flowering plants in the family Hypericaceae. It is made up of Hypericum aciferum, H. aegypticum, and H. russeggeri. When it was first described, it was considered its own independent genus, but was later placed under Hypericum and demoted to a section. Its Latin name Adenotrias is made of the Greek prefix adeno- and the Latin word trias. Species in the section are shrubs up to 2 metres (6.6 ft) tall with smooth leaves and bark, and are the only species in Hypericum with heterostylous flowers. They are found around the Mediterranean coast, with H. aciferum restricted to the island of Crete and H. russeggeri present only in parts of Turkey and Syria. Plants of the section have a habitat among limestone and other calcareous rocks. While H. aegypticum has a wide and generally secure distribution, H. aciferum was evaluated as endangered several times since the 1980s, although it is now considered only vulnerable because it is protected in part by a plant micro-reserve near Agia Roumeli.
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 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 aciferum is a species of flowering plant in the St John's wort family Hypericaceae. It is a small shrub endemic to the Greek island of Crete. H. aciferum grows in a mat on the ground and has twisting branches, needle-like leaves, and long golden petals. Its flowers are also heterostylous, which means that the species can exhibit one of two flower types on different plants. This trait is unique within the genus Hypericum to H. aciferum, H. russeggeri, and H. aegypticum, the three species in section Adenotrias.
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 minutum is a species of flowering plant in the St John's wort family Hypericaceae. It is a small perennial herb that grows in tufts. It has slender and brittle stems, flowers in clusters of one to three, yellow petals with black and amber glands, few stamens, and a seed capsule with narrow grooves. H. minutum is closely related to H. huber-morathii and H. sechmenii and resembles a smaller form of the latter plant. The plant is endemic to Turkey, and is found among limestone rocks in a limited region of southwestern Anatolia. Originally excluded from a comprehensive monograph of Hypericum, the species' placement within the genus is unclear. It has been placed in both section Adenosepalum and section Origanifolium.
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.
Hypericum foveolatum is an extinct species of the genus Hypericum. The paleospecies is known from more recent fossils than many other Hypericum specimens, with fossilized seeds from the Pliocene epoch being found in Russia and Belarus. These seeds have been compared to numerous extant species, including H. elegans, H. tetrapterum, H. attenuatum, H. kamtschaticum, H. yezoënse, H. nudiflorum, and H. microsepalum. However, none of these similar species have the exact same kind of testa surface cells as H. foveolatum.
Hypericum danicum is an extinct species of flowering plant in the family Hypericaceae. The species is known from a fossil seed found among other Hypericum seeds in Italy, and is dated to the Pliocene. It has also been recorded several times from the Søby region of Denmark, also by discovered fossil seeds.
Hypericum bornense is an extinct species of flowering plant in the family Hypericaceae. It was described by botanist D.H. Mai in 1978, based on fossil seed remains from the Early to Late Oligocene found in Saxony, Germany, and Tomsk, Russia. It is likely that the species' habitat was that of a mixed-mesophytic forest.
