| Northern St. John's-wort | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Malpighiales |
| Family: | Hypericaceae |
| Genus: | Hypericum |
| Section: | H. sect. Trigynobrathys |
| Species: | H. boreale |
| Binomial name | |
| Hypericum boreale | |
| Synonyms [1] | |
| |
Hypericum boreale, also known as northern St. John's-wort, is a short-lived perennial species of flowering plant in the family Hypericaceae, section Trigynobrathys .
The species was first described by British scientist Benjamin Britton as a subspecies of Hypericum mutilum, but Eugene Bicknell placed it as its own species in 1895 in the 22nd edition of the Bull. Torrey Bot. Club. [2] The species is most closely related to Hypericum mutilum , Hypericum majus , and Hypericum canadense . In addition to being similar in appearance, it is reported that the species hybridizes with at least H. canadense. [3]
The inflorescence of H. boreale is almost identical to that of Hypericum majus, but they differ in a few key ways. These include having more oblong and blunt sepals, fewer flowered clusters that are more leafy, and more broad and round leaves.
The inflorescence consists of single flowers or open clusters of a few to several flowers at the tips of stems and branches, with a pair of leaf-like bracts at the base of a flower stalk. Its flowers are yellow, and less than a quarter inch in diameter. It has with 5 narrow petals with blunt tips, 5 green sepals that have blunt tips, and 3 styles that are united at the base. Closely surrounding the center are 7 to 18 slender stamens. [4]
The leaves are simple, placed opposite and are either oblong, oval or elliptic. They are around half an inch long and a quarter of an inch wide. The tips and base are either rounded or taper to a blunt tip and there are 3 to 5 prominent veins. The stems are hairless and either branch on the upper part of the plant or from underground rhizomes. [4]
The fruit is an oval to ellipsoid capsule around an eighth of an inch long, and is a reddish to deep purple color. [4]
The species is found in the continental United States and parts of Canada. Specifically, its distribution is in the Pacific Northwest, the Midwest and Great Lakes regions, along the Eastern Seaboard, and in Eastern Canada. It shares a similar, but more limited, range to the related species H. majus. [4] [5]
The species is almost always found in wetlands. Specifically, it is often found on pond edges, stream banks, marshes, and bogs. [5] [6] It grows well in coarse and moderate, but not fine, soils. It is cold tolerant, but requires at least 90 frost-free days and cannot survive below −33 °F (−36 °C) for sustained periods of time. It is not tolerant of salt in the soil, and requires a pH between 4.4 and 6.0 in order to survive. [7]
While H. boreale is considered to be secure globally and nationally in the United States and Canada, it is still somewhat threatened because of fragmentation and habitat loss due to the disruption of wetlands. [8]
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 mutilum is a species of St. John's wort known by the common name dwarf St. John's wort. It is native to parts of North America and is present in other parts as an introduced species. It is an annual or perennial herb taking a multibranched erect form up to about 60 centimeters tall. The oval green leaves are one or two centimeters long and are covered in tiny glands. The inflorescence is a compound cyme of tiny flowers. H. mutilum subsp. mutilum and subsp. boreale have a diploid number of 16, and H. mutilum subsp. boreale can have a diploid number of 18.
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 dolabriforme, the straggling St. Johnswort or glade St. John's-wort, is a species of flowering plant in the St. John's wort family Hypericaceae native to the United States.
Hypericum terrae-firmae is a woody perennial flowering plant in the St. John's wort family Hypericaceae. It is an endemic plant species of Belize.
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 kalmianum, commonly called Kalm's St. Johns wort or Kalm's St. Johnswort, is a flowering plant in the St. John's wort family Hypericaceae. It is native to the Great Lakes region in the northern United States and southern Canada. Hypericum kalmianum was named after its discoverer, Swedish botanist Pehr Kalm (1715-1779).
Hypericum punctatum, the spotted St. John's wort, is a perennial herb native to North America. The yellow-flowered herb occurs throughout eastern North America into southern Canada. The process of microsporogenesis carried out by this plant is prone to errors in chromosomal segregation. It has a diploid number of 14 or 16. Insects are attracted to the plant's pollen and the hypericin in the plant's leaves is toxic to mammals.
Hypericum densiflorum, also known as bushy St. John's wort or dense St. John's wort, is a perennial herb in the flowering plant family Hypericaceae native to North America. The specific epithet densiflorum is Latin, meaning "densely flowered", referring to the many-flowered cymes.
Hypericum canadense, known as Canadian St. Johns-wort, lesser St. John's wort, and lesser Canadian St. Johnswort, is a flowering plant in the genus Hypericum. It is a yellow-flowering annual or perennial herb native to North America and introduced to Ireland and The Netherlands. The specific epithet canadense means "Canadian".
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 majus, the greater Canadian St. John's wort, is a perennial herb native to North America. The specific epithet majus means "larger". The plant has a diploid number of 16.
Hypericum lancasteri, known as Lancaster's St. John's wort or as zhan e jin si tao in Chinese, is a species of flowering plant in the St. John's wort family Hypericaceae. The species has been awarded the Royal Horticultural Society's Award of Garden Merit.
Hypericum assamicum is a species of flowering plant in the St. John's wort family, Hypericaceae. It is endemic to India. Hypericum assamicum is one of two species of Hypericum in the section Hypericum sect. Sampsonia.
Hypericum aucheri, also known as Koramanotu in Turkish, is a herbaceous perennial flowering plant in the St. John's wort family Hypericaceae.
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 harperi, the sharplobe St. Johnswort or Harper's St. John's wort, is a perennial flowering plant in the family Hypericaceae. It is an aquatic herb native to southeast North America. H. harperi has a diploid chromosome number of 24.
Hypericum vacciniifolium is a species of flowering plant in the flowering plant family Hypericaceae. It was first described by August von Hayek and Walter Siehe in the Ann. K. K. Naturhist. Hofmus. journal in 1914 from a specimen collected by Siehe in 1912.
Hypericum heterophyllum is a flowering plant in the Hypericaceae family and is the only species in Hypericum sect. Heterophylla.
This article incorporates public domain material from websites or documents of the United States Department of Agriculture .
