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Petrobium
''Petrobium'' is a genus in the family Asteraceae. The only known species is ''Petrobium arboreum'', called Saint Helena whitewood. It is found in the tree-fern thicket at the top of the central ridge of island of Saint Helena in the South Atlantic Ocean. The plants are either female or hermaphrodite, i.e. the species is gynodioecious.Flann, C (ed) 2009+ Global Compositae Checklist See also *Flora of St Helena The flora of Saint Helena, an isolated island in the South Atlantic Ocean, is exceptional in its high level of endemism and the severe threats facing ...
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Flora Of St Helena
The flora of Saint Helena, an isolated island in the South Atlantic Ocean, is exceptional in its high level of endemism and the severe threats facing the survival of the flora. In phytogeography, it is in the phytochorion St. Helena and Ascension Region of the African Subkingdom, in the Paleotropical Kingdom. Endemic and introduced flora The endemic plants of Saint Helena include many notable Cabbage Tree or, "insular arborescent Asteraceae", members of the daisy family which have evolved a shrubby or tree-like habit on islands. Other notable endemics include the closely related St Helena redwood ('' Trochetiopsis erythroxylon'') and St Helena dwarf ebony ('' Trochetiopsis ebenus''). These are unrelated to the redwood trees of California or to the ebony trees of commerce, being instead in the Mallow family (Malvaceae). Vegetation Today there are three major vegetation zones: the tree-fern thicket of the highest parts of the central ridge; the pastures of middle elevations and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flora Of Saint Helena
The flora of Saint Helena, an isolated island in the South Atlantic Ocean, is exceptional in its high level of endemism and the severe threats facing the survival of the flora. In phytogeography, it is in the phytochorion St. Helena and Ascension Region of the African Subkingdom, in the Paleotropical Kingdom. Endemic and introduced flora The endemic plants of Saint Helena include many notable Cabbage Tree or, "insular arborescent Asteraceae", members of the daisy family which have evolved a shrubby or tree-like habit on islands. Other notable endemics include the closely related St Helena redwood (''Trochetiopsis erythroxylon'') and St Helena dwarf ebony (''Trochetiopsis ebenus''). These are unrelated to the redwood trees of California or to the ebony trees of commerce, being instead in the Mallow family (Malvaceae). Vegetation Today there are three major vegetation zones: the tree-fern thicket of the highest parts of the central ridge; the pastures of middle elevations and the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coreopsideae
Coreopsideae is a tribe of flowering plants belonging to the Asteroideae subfamily. It includes widely cultivated genera such as ''Cosmos'' and ''Dahlia''. A similar group has been recognized since 1829, generally as part of the tribe Heliantheae ( Cassini, 1819). In the late 20th century, molecular studies caused a slightly redefined version of this group to be recognized as its own tribe, Coreopsideae. The larger version of Heliantheae was split into tribes including Bahieae, Chaenactideae, Coreopsideae, Helenieae and, finally, Heliantheae (''sensu stricto''). Within the tribe, the traditional definition of genera based on flower and fruit characters does not reflect evolutionary relationships as inferred through molecular phylogenetics. The tribe is characterized by shiny green bracts at the base of the flower head in two rows: an inner row of tightly spaced bracts and an outer row of a smaller number pointing downward. It includes five genera that use carbon fixation: '' Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Brown (botanist, Born 1773)
Robert Brown (21 December 1773 – 10 June 1858) was a Scottish botanist and paleobotanist who made important contributions to botany largely through his pioneering use of the microscope. His contributions include one of the earliest detailed descriptions of the cell nucleus and cytoplasmic streaming; the observation of Brownian motion; early work on plant pollination and fertilisation, including being the first to recognise the fundamental difference between gymnosperms and angiosperms; and some of the earliest studies in palynology. He also made numerous contributions to plant taxonomy, notably erecting a number of plant families that are still accepted today; and numerous Australian plant genera and species, the fruit of his exploration of that continent with Matthew Flinders. Early life Robert Brown was born in Montrose on 21 December 1773, in a house that existed on the site where Montrose Library currently stands. He was the son of James Brown, a minister in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melastomataceae
Melastomataceae is a family of dicotyledonous flowering plants found mostly in the tropics (two-thirds of the genera are from the New World tropics) comprising c. 175 genera and c. 5115 known species. Melastomes are annual or perennial herbs, shrubs, or small trees. Description The leaves of melastomes are somewhat distinctive, being opposite, decussate, and usually with 3-7 longitudinal veins arising either from the base of the blade, plinerved (inner veins diverging above base of blade), or pinnately nerved with three or more pairs of primary veins diverging from the mid-vein at successive points above the base. Flowers are perfect, and borne either singly or in terminal or axillary, paniculate cymes. Ecology A number of melastomes are regarded as invasive species once naturalized in tropical and subtropical environments outside their normal range. Examples are Koster's curse (''Clidemia hirta''), '' Pleroma semidecandrum'' and ''Miconia calvescens'', but many other specie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asparagaceae
Asparagaceae, known as the asparagus family, is a family of flowering plants, placed in the order Asparagales of the monocots. The family name is based on the edible garden asparagus, ''Asparagus officinalis''. Those who live in the temperate climates may be surprised to learn that this family includes both common garden plants as well as common houseplants. The garden plants include asparagus, yucca, bluebell, and hosta, and the houseplants include snake plant, corn cane, spider plant and plumosus fern. Taxonomy In earlier classification systems, the species involved were often treated as belonging to the family Liliaceae. The APG II system of 2003 allowed two options as to the circumscription of the family: either Asparagaceae ''sensu lato'' ("in the wider sense") combining seven previously recognized families, or Asparagaceae ''sensu stricto'' ("in the strict sense") consisting of very few genera (notably ''Asparagus'', also ''Hemiphylacus''), but nevertheless totalling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rutaceae
The Rutaceae is a family, commonly known as the rueRUTACEAE in BoDD – Botanical Dermatology Database or family, of s, usually placed in the order . Species of the family generally have s that divide into four or five parts, usually w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubiaceae
The Rubiaceae are a family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with interpetiolar stipules and sympetalous actinomorphic flowers. The family contains about 13,500 species in about 620 genera, which makes it the fourth-largest angiosperm family. Rubiaceae has a cosmopolitan distribution; however, the largest species diversity is concentrated in the tropics and subtropics. Economically important genera include ''Coffea'', the source of coffee, '' Cinchona'', the source of the antimalarial alkaloid quinine, ornamental cultivars (''e.g.'', '' Gardenia'', ''Ixora'', ''Pentas''), and historically some dye plants (''e.g.'', ''Rubia''). Description The Rubiaceae are morphologically easily recognizable as a coherent group by a combination of characters: opposite or whorled leaves that are simple and entire, interpetiolar stipules, tubu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteraceae
The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae were first described in the year 1740. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger family is unclear as the quantity of extant species in each family is unknown. Most species of Asteraceae are annual, biennial, or perennial herbaceous plants, but there are also shrubs, vines, and trees. The family has a widespread distribution, from subpolar to tropical regions in a wide variety of habitats. Most occur in hot desert and cold or hot semi-desert climates, and they are found on every continent but Antarctica. The primary common characteristic is the existence of sometimes hundreds of tiny individual florets which are held together by protective involucres in flower heads, or more technicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint Helena
Saint Helena () is a British overseas territory located in the South Atlantic Ocean. It is a remote volcanic tropical island west of the coast of south-western Africa, and east of Rio de Janeiro in South America. It is one of three constituent parts of the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha. Saint Helena measures about and has a population of 4,439 per the 2021 census. It was named after Helena, mother of Constantine I. It is one of the most remote islands in the world and was uninhabited when discovered by the Portuguese enroute to the Indian subcontinent in 1502. For about four centuries the island was an important stopover for ships from Europe to Asia and back, while sailing around the African continent, until the opening of the Suez canal. St Helena is the United Kingdom's second-oldest overseas territory after Bermuda. Saint Helena is known for being the site of Napoleon's second exile, following his final defeat in 1815. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and Asia from the "New World" of the Americas in the European perception of the World. The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and North and South America to the west. As one component of the interconnected World Ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other definitions describe the Atlantic as extending southward to Antarctica). The Atlantic Ocean is divided in two parts, by the Equatorial Counter Current, with the North(ern) Atlantic Ocean and the South(ern) Atlantic Ocean split at about 8°N. Scientific explorations of the Atlantic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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