|
Loefgrenia (cyanobacteria)
''Loefgrenia'' is a monospecific, freshwater, epiphytic genus of nonheterocystic cyanobacteria known from Brazil. The type and only known species for the genus is ''Loefgrenia anomala''. The genus name of ''Loefgrenia'' is in honour of Johan Albert Constantin Löfgren (1854–1918), known as Albert Löfgren or Alberto Löfgren, was head of the botany department of the Rio de Janeiro Botanical Garden around 1905. The genus was circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ... by Maurice Augustin Gomont in Alg. Aq. Dulc. Exsicc. on page 1350 in 1896. References Nostocales {{cyanobacteria-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maurice Augustin Gomont
Maurice-Augustin Gomont (born 1839, in Rouen – died 1909, in Rouen) was a French phycologist. Works * Gomont, M (1892). "Monographie des Oscillariées (Nostocacées Homocystées). Deuxième partie. - Lyngbyées". Annales des Sciences Naturelles, Botanique. 7 (16). Honours * ''Gomontia'', which is a genus of green algae, in the family Gomontiaceae and also Gomontiellaceae, which is a family of cyanobacteria, were both named in 1888 by botanists Jean-Baptiste Édouard Bornet and Charles Henri Marie Flahault after Maurice Gomont. * ''Gomontiellaceae'' are a family of cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ..., with ''Gomontiella'', a species named in 1901. References Further reading * 1839 births 1909 deaths Scientists from Rouen French phycolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Veit Brecher Wittrock
Veit Brecher Wittrock (5 May 1839 at district of Dalsland – 1 September 1914 in Stockholm) was a Swedish botanist known for his work in the field of phycology and for his research of the genus ''Viola''. Biography From 1857 to 1865 he studied at the University of Uppsala, then spent the next thirteen years as a gymnasium teacher in Uppsala. In 1878 he became an associate professor at the University of Uppsala. From 1879 to 1904 he served as a professor and curator of the botanical collections at the '' Naturhistoriska riksmuseet'' in Stockholm. In Stockholm, he was also a professor and director of the '' Bergianska trädgården'' (1879–1914).BHL Taxonomic literature : a selective guide to botanical publications Botanical eponymy * '' |
Fresh Water
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salt (chemistry), salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mineral water, mineral-rich waters, such as chalybeate springs. Fresh water may encompass frozen water, frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/ice pellets, sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranea (geography), subterranean subterranean river, rivers and underground lake, lakes. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of vascular plants and most insects, amphibians, reptiles, mammals and birds need fresh water to sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epiphyte
An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phorophytes. Epiphytes take part in nutrient cycles and add to both the diversity and biomass of the ecosystem in which they occur, like any other organism. In some cases, a rainforest tree's epiphytes may total "several tonnes" (several long tons). They are an important source of food for many species. Typically, the older parts of a plant will have more epiphytes growing on them. Epiphytes differ from parasites in that they grow on other plants for physical support and do not necessarily affect the host negatively. An organism that grows on another organism that is not a plant may be called an epibiont. Epiphytes are usually found in the temperate zone (e.g., many mosses, liverworts, lichens, and algae) or in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyst
Heterocysts or heterocytes are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as ''Nostoc'', ''Cylindrospermum'', and '' Anabaena''. They fix nitrogen from dinitrogen (N2) in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis. Nitrogenase is inactivated by oxygen, so the heterocyst must create a microanaerobic environment. The heterocysts' unique structure and physiology require a global change in gene expression. For example, heterocysts: * produce three additional cell walls, including one of glycolipid that forms a hydrophobic barrier to oxygen * produce nitrogenase and other proteins involved in nitrogen fixation * degrade photosystem II, which produces oxygen * up-regulate glycolytic enzymes * produce proteins that scavenge any remaining oxygen * contain polar plugs composed of cyanophycin which slows down cell-to-cell diffusion Cyanobacteria usu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanobacteria
Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteria's informal common name, blue-green algae. Cyanobacteria are probably the most numerous taxon to have ever existed on Earth and the first organisms known to have produced oxygen, having appeared in the middle Archean eon and apparently originated in a freshwater or terrestrial environment. Their photopigments can absorb the red- and blue-spectrum frequencies of sunlight (thus reflecting a greenish color) to split water molecules into hydrogen ions and oxygen. The hydrogen ions are used to react with carbon dioxide to produce complex organic compounds such as carbohydrates (a process known as carbon fixation), and the oxygen is released as a byproduct. By continuously producing and releasing oxygen over billions of years, cyanobacte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brazil
Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population, seventh-largest by population, with over 212 million people. The country is a federation composed of 26 Federative units of Brazil, states and a Federal District (Brazil), Federal District, which hosts the capital, Brasília. List of cities in Brazil by population, Its most populous city is São Paulo, followed by Rio de Janeiro. Brazil has the most Portuguese-speaking countries, Portuguese speakers in the world and is the only country in the Americas where Portuguese language, Portuguese is an Portuguese-speaking world, official language. Bounded by the Atlantic Ocean on the east, Brazil has a Coastline of Brazil, coastline of . Covering roughly half of South America's land area, it Borders of Brazil, borders all other countries and ter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Species
In International_Code_of_Zoological_Nomenclature, 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 (biology), type wiktionary:en:specimen, specimen (or specimens). 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 International Code of Nomenclature for algae, fungi, and plants, 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 with 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 suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotypic Taxon
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of Genus, genera, the term "unispecific" or "monospecific" is sometimes preferred. In botanical nomenclature, a monotypic genus is a genus in the special case where a genus and a single species are simultaneously described. Theoretical implications Monotypic taxa present several important theoretical challenges in biological classification. One key issue is known as "Gregg's Paradox": if a single species is the only member of multiple hierarchical levels (for example, being the only species in its genus, which is the only genus in its family), then each level needs a distinct definition to maintain logical structure. Otherwise, the different taxonomic ranks become effectively identical, which creates problems for organizing biological diversity in a hierarchical o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johan Albert Constantin Löfgren
Johan Albert Constantin Löfgren (1854–1918), known as Albert Löfgren or Alberto Löfgren, was head of the botany department of the Rio de Janeiro Botanical Garden around 1905. The plant currently known as '' Schlumbergera opuntioides'' is one of those he first named. Löfgren was the first director of the Horto Florestal de São Paulo, from 1907 to 1909, now named the Albert Löfgren State Park. He is honoured in the naming of '' Loefgrenia'', which is a monospecific, freshwater, epiphytic genus of nonheterocystic cyanobacteria known from Brazil, and the monotypic orchid genus of ''Loefgrenianthus ''Loefgrenianthus blanche-amesiae'' is a showy orchid species, inhabitant of Serra do Mar mountains in Brazilian southeast. It is the only species of the monotypic genus ''Loefgrenianthus''. It can be differentiated from its closest genus, '' Lep ...'' from SE Brasil. References 1854 births 1918 deaths 20th-century Brazilian botanists 19th-century Brazilian botanists S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rio De Janeiro Botanical Garden
The Rio de Janeiro Botanical Garden or Jardim Botânico is located at the Jardim Botânico district in the South Zone of Rio de Janeiro. The Botanical Garden shows the diversity of Brazilian and foreign flora. There are around 6,500 species (some endangered) distributed throughout an area of as well as numerous greenhouses. The garden also houses monuments of historical, artistic, and archaeological significance. There is an important research center, which includes the most complete library in the country specializing in botany with over 32,000 volumes. It was founded in 1808 by King John VI of Portugal. Originally intended for the acclimatization of spices like nutmeg, pepper and cinnamon imported from the West Indies, the garden was opened to the public in 1822, and is now open during daylight hours every day except 25 December and 1 January. The park lies at the foot of the Corcovado Mountain, far below the right arm of the statue of '' Christ the Redeemer'' and contai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumscription (taxonomy)
In biological taxonomy, circumscription is the content of a taxon, that is, the delimitation of which subordinate taxa are parts of that taxon. For example, if we determine that species X, Y, and Z belong in genus A, and species T, U, V, and W belong in genus B, those are our circumscriptions of those two genera. Another systematist might determine that T, U, V, W, X, Y, and Z all belong in genus A. Agreement on circumscriptions is not governed by the Codes of Zoological or Botanical Nomenclature, and must be reached by scientific consensus. A goal of biological taxonomy is to achieve a stable circumscription for every taxon. This goal conflicts, at times, with the goal of achieving a natural classification that reflects the evolutionary history of divergence of groups of organisms. Balancing these two goals is a work in progress, and the circumscriptions of many taxa that had been regarded as stable for decades are in upheaval in the light of rapid developments in molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
