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Welwitschia
''Welwitschia'' is a monotypic gymnosperm genus, comprising solely the distinctive ''Welwitschia mirabilis'', endemic to the Namib desert within Namibia and Angola. ''Welwitschia'' is the only living genus of the family Welwitschiaceae and order Welwitschiales in the division Gnetophyta, and is one of three living genera in Gnetophyta, alongside ''Gnetum'' and ''Ephedra''. Informal sources commonly refer to the plant as a "living fossil". Naming ''Welwitschia'' is named after the Austrian botanist and doctor Friedrich Welwitsch, who described the plant in Angola in 1859. Welwitsch was so overwhelmed by the plant that he, "could do nothing but kneel down ..and gaze at it, half in fear lest a touch should prove it a figment of the imagination." Joseph Dalton Hooker of the Linnean Society of London, using Welwitsch's description and collected material along with material from the artist Thomas Baines who had independently recorded the plant in Namibia, described the species. Wel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welwitschia Mirabilis00
''Welwitschia'' is a monotypic gymnosperm genus, comprising solely the distinctive ''Welwitschia mirabilis'', endemic to the Namib desert within Namibia and Angola. ''Welwitschia'' is the only living genus of the family Welwitschiaceae and order Welwitschiales in the division Gnetophyta, and is one of three living genera in Gnetophyta, alongside '' Gnetum'' and '' Ephedra''. Informal sources commonly refer to the plant as a " living fossil". Naming ''Welwitschia'' is named after the Austrian botanist and doctor Friedrich Welwitsch, who described the plant in Angola in 1859. Welwitsch was so overwhelmed by the plant that he, "could do nothing but kneel down ..and gaze at it, half in fear lest a touch should prove it a figment of the imagination." Joseph Dalton Hooker of the Linnean Society of London, using Welwitsch's description and collected material along with material from the artist Thomas Baines who had independently recorded the plant in Namibia, described t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnetophyta
Gnetophyta () is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict genera: ''Gnetum'' (family Gnetaceae), ''Welwitschia'' (family Welwitschiaceae), and ''Ephedra'' (family Ephedraceae). Fossilized pollen attributed to a close relative of ''Ephedra'' has been dated as far back as the Early Cretaceous. Though diverse in the Early Cretaceous, only three families, each containing a single genus, are still alive today. The primary difference between gnetophytes and other gymnosperms is the presence of vessel elements, a system of conduits that transport water within the plant, similar to those found in flowering plants. Because of this, gnetophytes were once thought to be the closest gymnosperm relatives to flowering plants, but more recent molecular studies have brought this hypothesis into question. Thou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welwitschiales
Welwitschiaceae is a family of plants of the order Gnetales with one living species, '' Welwitschia mirabilis'', found in southwestern Africa. Three fossil genera have been recovered from the Crato Formation – late Aptian ( Lower Cretaceous) strata located in the Araripe Basin in northeastern Brazil, with one of these also being known from the early Late Cretaceous (Cenomanian- Turonian) Akrabou Formation of Morocco. Taxonomy German naturalist Friedrich Markgraf coined the name Welwitschiaceae in 1926, which appeared in '' Die Natürlichen Pflanzenfamilien''. Most recent systems place the Welwitschiaceae in the gymnosperm order Gnetales. This order is most closely related to the order Pinales, which includes Araucariaceae - Araucarians, Cupressaceae - Cypress Family, Pinaceae - Pine Family, Podocarpaceae - Podocarps, Sciadopityaceae - Koyamaki Family (the sole membeSciadopitys verticillata - Koyamaki, Taxaceae - Yew Family. Genetic analyses indicate that the Gneta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welwitschiaceae
Welwitschiaceae is a family of plants of the order Gnetales with one living species, '' Welwitschia mirabilis'', found in southwestern Africa. Three fossil genera have been recovered from the Crato Formation – late Aptian ( Lower Cretaceous) strata located in the Araripe Basin in northeastern Brazil, with one of these also being known from the early Late Cretaceous (Cenomanian- Turonian) Akrabou Formation of Morocco. Taxonomy German naturalist Friedrich Markgraf coined the name Welwitschiaceae in 1926, which appeared in '' Die Natürlichen Pflanzenfamilien''. Most recent systems place the Welwitschiaceae in the gymnosperm order Gnetales. This order is most closely related to the order Pinales, which includes Araucariaceae - Araucarians, Cupressaceae - Cypress Family, Pinaceae - Pine Family, Podocarpaceae - Podocarps, Sciadopityaceae - Koyamaki Family (the sole membeSciadopitys verticillata - Koyamaki, Taxaceae - Yew Family. Genetic analyses indicate that the Gneta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnetales
Gnetophyta () is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict genera: ''Gnetum'' (family Gnetaceae), ''Welwitschia'' (family Welwitschiaceae), and ''Ephedra'' (family Ephedraceae). Fossilized pollen attributed to a close relative of ''Ephedra'' has been dated as far back as the Early Cretaceous. Though diverse in the Early Cretaceous, only three families, each containing a single genus, are still alive today. The primary difference between gnetophytes and other gymnosperms is the presence of vessel elements, a system of conduits that transport water within the plant, similar to those found in flowering plants. Because of this, gnetophytes were once thought to be the closest gymnosperm relatives to flowering plants, but more recent molecular studies have brought this hypothesis into question. Thoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friedrich Welwitsch
Friedrich Martin Josef Welwitsch (25 February 1806 – 20 October 1872) was an Austrian explorer and botanist who in Angola was the first European to describe the plant '' Welwitschia mirabilis''. His report received wide attention among the botanists and general public, comparable only to the discovery of two other plants in the 19th century, namely '' Victoria amazonica'' and '' Rafflesia arnoldii''.Strlič, Matija. "Dr. Friderik Velbič, 1806–1872". ''Proteus, the journal of the Natural Sciences Society of Slovenia''. Year 61, No. 9/10 (pp. 396-404). ISSN 0033-1805. In Angola, Welwitsch also discovered '' Rhipsalis baccifera'', the only cactus species naturally occurring outside the New World. It was found a few years later in Sri Lanka too, which reignited the now already one-and-a-half-century-old debate on the origin of cacti in Africa and Asia. At the time, the debate concluded with the conviction of numerous authors that they were introduced and spread by migrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnosperm
The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, ''Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμνόσπερμος ( el, γυμνός, translit=gymnos, lit=naked, label=none and el, σπέρμα, translit=sperma, lit=seed, label=none), literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in yew, ''Torreya'', ''Ginkgo''. Gymnosperm lifecycles involve alternation of generations. They have a dominant diploid sporophyte phase and a reduced haploid gametophyte phase which is dependent on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Namib Desert
The Namib ( ; pt, Namibe) is a coastal desert in Southern Africa. The name is of Khoekhoegowab origin and means "vast place". According to the broadest definition, the Namib stretches for more than along the Atlantic coasts of Angola, Namibia, and South Africa, extending southward from the Carunjamba River in Angola, through Namibia and to the Olifants River (Western Cape), Olifants River in Western Cape, South Africa. The Namib's northernmost portion, which extends from the Angola-Namibia border, is known as Moçâmedes Desert, while its southern portion approaches the neighboring Kalahari Desert. From the Atlantic coast eastward, the Namib gradually ascends in elevation, reaching up to inland to the foot of the Great Escarpment, Southern Africa, Great Escarpment. Annual precipitation ranges from in the most arid regions to at the escarpment, making the Namib the only true desert in southern Africa. Having endured Desert climate, arid or Semi-arid climate, semi-arid cond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Living Fossil
A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossils commonly are of species-poor lineages, but they need not be. While the body plan of a living fossil remains superficially similar, it is never the same species as the remote relatives it resembles, because genetic drift would inevitably change its chromosomal structure. Living fossils exhibit stasis (also called "bradytely") over geologically long time scales. Popular literature may wrongly claim that a "living fossil" has undergone no significant evolution since fossil times, with practically no molecular evolution or morphological changes. Scientific investigations have repeatedly discredited such claims. The minimal superficial changes to living fossils are mistakenly declared as an absence of evolution, but they are examples of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ephedra (plant)
''Ephedra'' is a genus of gymnosperm shrubs. The various species of ''Ephedra'' are widespread in many arid regions of the world, ranging across southwestern North America, southern Europe, northern Africa, southwest and central Asia, northern China and western South America. It is the only extant genus in its family, Ephedraceae, and order, Ephedrales, and one of the three living members of the division Gnetophyta alongside ''Gnetum'' and ''Welwitschia.'' In temperate climates, most ''Ephedra'' species grow on shores or in sandy soils with direct sun exposure. Common names in English include joint-pine, jointfir, Mormon-tea or Brigham tea. The Chinese name for ''Ephedra'' species is ''mahuang'' (). ''Ephedra'' is the origin of the name of the stimulant ephedrine, which the plants contain in significant concentration. Description The family Ephedraceae, of which ''Ephedra'' is the only genus, are gymnosperms, and generally shrubs, sometimes clambering vines, and rarely, smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnetum
''Gnetum'' is a genus of gymnosperms, the sole genus in the family Gnetaceae within the Gnetophyta. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect-pollinated as their fossils occur in association with extinct pollinating scorpionflies.Ren D, Labandeira CC, Santiago-Blay JA, Rasnitsyn A, Shih CK, Bashkuev A, Logan MA, Hotton CL, Dilcher D. (2009). Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies. Science, 326 (5954), 840-847. Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species. Fossil-calibrated molecular-clocks suggest that the ''Gnetum'' lineages now found in Africa, South America and Southeast Asia are the result of ancient long-distance dispersal across seawater.Won H, Renner SS: The internal tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nama Language
The Khoekhoe language (), also known by the ethnic terms Nama (''Namagowab'') , Damara (''ǂNūkhoegowab''), or Nama/Damara and formerly as Hottentot, is the most widespread of the non-Bantu languages of Southern Africa that make heavy use of click consonants and therefore were formerly classified as Khoisan, a grouping now recognized as obsolete. It belongs to the Khoe language family, and is spoken in Namibia, Botswana, and South Africa primarily by three ethnic groups: Namakhoen, ǂNūkhoen, and Haiǁomkhoen. History The Haiǁom, who had spoken a Juu language, later shifted to Khoekhoe. The name for the speakers, ''Khoekhoen'', is from the word ''khoe'' "person", with reduplication and the suffix ''-n'' to indicate the general plural. Georg Friedrich Wreede was the first European to study the language, after arriving in ǁHui!gaeb (later Cape Town) in 1659. Status Khoekhoe is a national language in Namibia. In Namibia and South Africa, state-owned broadcasting corpo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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