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Christensenia (plant)
''Christensenia'' is a genus of ferns in the botanical family Marattiaceae. The genus is confined to the Indo-Malayan region. The basal chromosome number for this genus is 2n=80. ''Christensenia'' is unique in the Marattiaceae, because of its reticulate venation, palmately arranged leaves and radial synangia. ''Christensenia'' produces enormous amounts of spores, up to 7,000 spores per sporangium. The presence of a radial synangium is an archaic character, very similar to some of the fossil Asterothecaceae/ Psaroniaceae, such as '' Scolecopteris''. ''Christensenia'' itself has no fossil record. Species After the 1993 revision by Rolleri, only two species and one variety Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ... are recognized: * ''Christensenia aesculifolia'' (Carl L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Ralph Maxon
William Ralph Maxon, (February 27, 1877February 25, 1948) was an American botanist and pteridologist. He graduated from Syracuse University with a Bachelor of Philosophy, B.Ph. in biology, in 1898, and spent about one year at Columbia University doing post-graduate work on ferns with Lucien Marcus Underwood. In 1899 he accepted a position with the National Museum of Natural History, United States National Museum, which was a part of the Smithsonian Institution; he remained at the museum for his entire career. In 1899 he became an aide with the Division of Plants. He was named assistant curator in 1905, associate curator in 1914, and curator of that Division in 1937. He retired in 1946, but continued his association with the museum until his death in 1948. For the current version of this webpage, see . The later version does not indicate authorship. Alan Bain has written that, "Maxon specialized in the taxonomic study of Pteridophyta, especially those of tropical America, and was con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Project Gutenberg
Project Gutenberg (PG) is a Virtual volunteering, volunteer effort to digitize and archive cultural works, as well as to "encourage the creation and distribution of eBooks." It was founded in 1971 by American writer Michael S. Hart and is the oldest digital library. Most of the items in its collection are the full texts of books or individual stories in the public domain. All files can be accessed for free under an open format layout, available on almost any computer. , Project Gutenberg had reached 50,000 items in its collection of free eBooks. The releases are available in Text file, plain text as well as other formats, such as HTML, PDF, EPUB, Mobipocket, MOBI, and Plucker wherever possible. Most releases are in the English language, but many non-English works are also available. There are multiple affiliated projects that provide additional content, including region- and language-specific works. Project Gutenberg is closely affiliated with Distributed Proofreaders, an Inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kew Gardens
Kew Gardens is a botanical garden, botanic garden in southwest London that houses the "largest and most diverse botany, botanical and mycology, mycological collections in the world". Founded in 1840, from the exotic garden at Kew Park, its living collections include some of the 27,000 taxa curated by Royal Botanic Gardens, Kew, while the herbarium, one of the largest in the world, has over preserved plant and fungal specimens. The library contains more than 750,000 volumes, and the illustrations collection contains more than 175,000 prints and drawings of plants. It is one of London's top tourist attractions and is a World Heritage Sites, World Heritage Site. Kew Gardens, together with the botanic gardens at Wakehurst Place, Wakehurst in Sussex, are managed by the Royal Botanic Gardens, Kew, an internationally important botany, botanical research and education institution that employs over 1,100 staff and is a non-departmental public body sponsored by the Department for Envir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Willem Hendrik De Vriese
Willem Hendrik de Vriese (11 August 1806 – 23 January 1862) was a Dutch botanist and physician born in Oosterhout, North Brabant. Education Willem Hendrik de Vriese studied medicine at the University of Leiden, earning his doctorate in 1831. Career He practiced medicine in Rotterdam, where he also gave classes in botany at the medical school. In 1834, he was appointed associate professor of botany at the Athenaeum Illustre of Amsterdam, Athenaeum Illustré in Amsterdam, and in 1841 was promoted to full professor. In 1845, he became a professor of botany at Leiden and successor to Caspar Georg Carl Reinwardt (1773–1854) at the ''Hortus Botanicus Leiden''. He became a member of the Royal Netherlands Academy of Arts and Sciences, Royal Dutch Institute of Sciences, Literature and Fine Arts in 1838. In October 1857, he was commissioned to conduct botanical investigations in the Dutch East Indies, and consequently spent the following years performing research in Java, Borne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christensenia Lobbiana ''
{{Genus disambiguation ...
''Christensenia'' is the scientific name of two genera of organisms and may refer to: * ''Christensenia'' (beetle) Brinck, 1945, a genus of beetles in the family Curculionidae * ''Christensenia'' (plant), a genus of ferns in the family Marattiaceae *''Christensia'' Dózsa-Farkas & Convey, 1997, a genus of oligochaete worms in the family Enchytraeidae, and a junior homonym of ''Christensenia'' Brinck, 1945, replaced by ''Christensenidrilus ''Christensenidrilus'' is a genus of annelids belonging to the family Enchytraeidae. Species: * ''Christensenidrilus blocki'' (Dózsa-Farkas & Convey, 1997) References {{Taxonbar, from=Q18519106 Annelids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen(s). Article 67.1 A similar concept is used for suprageneric groups and called a type genus. In botanical nomenclature, these terms have no formal standing under the code of nomenclature, but are sometimes borrowed from zoological nomenclature. In botany, the type of a genus name is a specimen (or, rarely, an illustration) which is also the type of a species name. The species name that has that type can also be referred to as the type of the genus name. Names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have such types. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Ludwig Blume
Charles Ludwig de Blume or Karl Ludwig von Blume (9 June 1796, Braunschweig – 3 February 1862, Leiden) was a German-Dutch botanist. He was born at Braunschweig in Germany, but studied at Leiden University and spent his professional life working in the Dutch East Indies and in the Netherlands, where he was Director of the Rijksherbarium (state herbarium) at Leiden. His name is sometimes given in the Dutch language form Karel Lodewijk Blume, but the original German spelling is the one most widely used in botanical texts: even then there is confusion, as he is sometimes referred to as K.L. Blume (from Karl). He carried out extensive studies of the flora of southern Asia, particularly in Java, then a colony of the Netherlands. From 1823 to 1826 Blume was Deputy Director of Agriculture at the botanic garden in Bogor (Buitenzorg) in Java. In 1827 he became correspondent of the Royal Institute of the Netherlands. In 1855, he was elected a foreign member of the Royal Swedish Ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variety (botany)
In botanical nomenclature, variety (abbreviated var.; in la, varietas) is a taxonomic rank below that of species and subspecies, but above that of form. As such, it gets a three-part infraspecific name. It is sometimes recommended that the subspecies rank should be used to recognize geographic distinctiveness, whereas the variety rank is appropriate if the taxon is seen throughout the geographic range of the species. Example The pincushion cactus, ''Escobaria vivipara'' (Nutt.) Buxb., is a wide-ranging variable species occurring from Canada to Mexico, and found throughout New Mexico below about . Nine varieties have been described. Where the varieties of the pincushion cactus meet, they intergrade. The variety ''Escobaria vivipara'' var. ''arizonica'' is from Arizona, while ''Escobaria vivipara'' var. ''neo-mexicana'' is from New Mexico. See also '' Capsicum annuum var. glabriusculum'' Definitions The term is defined in different ways by different authors. However, the I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Record
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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