Hypericum perforatum, commonly known as St John's wort, is a flowering plant in the family Hypericaceae. It is a perennial plant that grows up to one meter tall, with many yellow flowers that have clearly visible black glands around their edges, long stamens, and three pistils. Probably a hybrid between the closely related H. attenuatum and H. maculatum that originated in Siberia, the species is now found worldwide. 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.
Actaea spicata, the baneberry or herb Christopher, is a species of flowering plant in the genus Actaea, native from Europe to western Siberia and northern Iran. It is often found on limestone edges and in deciduous woodland; key factors are shade, low competition, and a cool, protected root run.
Clive Anthony Stace is a British botanist and botanical author. He studied at King's College London, graduated from University of London in 1959 and then studied at the Natural History Museum, London. He was awarded a PhD in 1963. His academic career was based at the University of Leicester, where he held the post of Professor of Plant taxonomy. He is a past president of the Botanical Society of Britain and Ireland from 1987 to 1989.
Hypericum maculatum, commonly known as imperforate St John's-wort, or spotted St. Johnswort, is a species of perennial herbaceous flowering plant in the family Hypericaceae. It is native to Europe and Western Asia where it grows in moist meadows.
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 hirsutum is a species of flowering plant in the family Hypericaceae, commonly known as hairy St John's-wort. It is found in Western Europe.
Hypericum rumeliacum is a species of flowering plant in the family Hypericaceae, native to southeastern Europe.
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 aciculare is a shrub in the genus Hypericum, in the section Brathys. It is an accepted name according to The Plant List and Tropicos.
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.
Hypericum lanuginosum, or downy St. John's wort, is a perennial herb, a flowering plant in the St. John's wort family Hypericaceae.
Hypericum pubescens is a perennial herb in the Hypericaceae family. It is in the section Adenosepalum.
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 vitrio antibiotic and antioxidizing capabilities.
Hypericum hookerianum, or Hooker's St. John's Wort, is a perennial shrub in the flowering plant family Hypericaceae native to eastern and southern Asia. The specific name hookerianum is named for William Jackson Hooker.
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.
Koenigia × fennica, known as Finnish knotweed, is a hybrid between two species of Koenigia, K. alpina and K. weyrichii, members of the family Polygonaceae, the knotweed family. It generally only known as a cultivated garden plant, but plants have been recorded a few times surviving in abandoned areas in northern Europe, especially in Finland. The cultivar 'Johanniswolke' is considered an attractive ornamental perennial plant.
Hypericum pallens, commonly known as the Pale St. John's wort or Mount Lebanon St. John's wort, is a species of flowering plant in the family Hypericaceae which is found in Turkey, Lebanon, and Syria.
Silene italica is a species of plant native to Southern Europe and parts of Asia. It is also introduced to parts of the United States and Northern Europe.
