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Myriopteris Rawsonii
''Myriopteris rawsonii'', formerly known as ''Cheilanthes rawsonii'', is a perennial fern native to Namaqualand in Southern Africa. Like many other cheilanthoid ferns, it is adapted to dry conditions, bearing a thick layer of pale hairs on the underside of its pinnate-pinnatifid leaves. It is the only African representative of its clade of cheilanthoids, the otherwise American genus ''Myriopteris''. It spends much of the year in a dried-out, dormant state, rehydrating and putting out new growth during winter rains. Its name honors the botanist and civil servant Sir Rawson W. Rawson. Description The fronds arise from a creeping rhizome about in diameter. The rhizome bears linear scales up to long, which are blackish-brown in color, growing pale brown at the margins. The scales are jagged at the edges, or ciliate (bearing hair-like projections). The fronds are closely spaced along the rhizome, standing erect or arching somewhat. They emerge as fiddleheads (circinate vernation) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Wilhelm Ludwig Pappe
Karl (or "Carl") Wilhelm Ludwig Pappe (1803, in Hamburg – 14 October 1862) was a German-born physician and botanist who lived and worked in South Africa. He was the first person to hold the position of government botanist and the first professor of botany at the South African College. His herbarium became the oldest surviving botanical collection in South Africa. Biography Pappe studied medicine and botany at the Leipzig University. He qualified in medicine in 1827 with a thesis on the flowering plants of Leipzig, ''"Enumerationes plantarum phaenogamarum lipsiensium specimen"''. Medical career He travelled to Cape Town in January 1831 and was registered as a physician, surgeon and accoucheur (a male obstetrician). He joined the South African Medical Society in 1832 and was one of three doctors in charge of the temporary hospital in Cape Town during the measles epidemic of 1839. From 1855 to 1858 he served as physician to the European Sick and Burial Society and the Widow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipinnate
The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular or irregular, may be smooth or bearing hair, bristles or spines. For more terms describing other aspects of leaves besides their overall morphology see the leaf article. The terms listed here all are supported by technical and professional usage, but they cannot be represented as mandatory or undebatable; readers must use their judgement. Authors often use terms arbitrarily, or coin them to taste, possibly in ignorance of established terms, and it is not always clear whether because of ignorance, or personal preference, or because usages change with time or context, or because of variation between specimens, even specimens from the same plant. For example, whether to call leaves on the same tree "acuminate", "lanceolate", or "linear" could ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michael D
Michael D may refer to: * Mike D (born 1965), founding member of the Beastie Boys Arts * Michael D. Cohen (actor) (born 1975), Canadian actor * Michael D. Ellison, African American recording artist * Michael D. Fay, American war artist * Michael D. Ford (1928–2018), English set decorator * Michael D. Roberts, American actor Business * Michael D. Dingman (1931–2017), American businessman * Michael D. Ercolino (1906–1982), American businessman * Michael D. Fascitelli, (born c. 1957), American businessman * Michael D. Penner (born 1969), Canadian lawyer and businessman Education * Michael D. Aeschliman (born 1948), American–Swiss educator * Michael D. Cohen (academic) (1945–2013), professor of complex systems, information and public policy at the University of Michigan * Michael D. Hanes, American music educator * Michael D. Hurley (born 1976), British Professor of Literature and Theology * Michael D. Johnson, a former President of John Carroll University * Michael D. Kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homoplasy
Homoplasy, in biology and phylogenetics, is the term used to describe a feature that has been gained or lost independently in separate lineages over the course of evolution. This is different from homology, which is the term used to characterize the similarity of features that can be parsimoniously explained by common ancestry. Homoplasy can arise from both similar selection pressures acting on adapting species, and the effects of genetic drift. Most often, homoplasy is viewed as a similarity in morphological characters. However, homoplasy may also appear in other character types, such as similarity in the genetic sequence, life cycle types or even behavioral traits. Etymology The term homoplasy was first used by Ray Lankester in 1870. The corresponding adjective is either ''homoplasic'' or ''homoplastic''. It is derived from the two Ancient Greek words (), meaning "similar, alike, the same", and (), meaning "to shape, to mold". Parallelism and convergence Parallel a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas ''homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to paralle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyphyly
A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of convergent evolution. The arrangement of the members of a polyphyletic group is called a polyphyly .. ource for pronunciation./ref> It is contrasted with monophyly and paraphyly. For example, the biological characteristic of warm-bloodedness evolved separately in the ancestors of mammals and the ancestors of birds; "warm-blooded animals" is therefore a polyphyletic grouping. Other examples of polyphyletic groups are algae, C4 photosynthetic plants, and edentates. Many taxonomists aim to avoid homoplasies in grouping taxa together, with a goal to identify and eliminate groups that are found to be polyphyletic. This is often the stimulus for major revisions of the classification schemes. Researchers concerned more with ecology than with syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Phylogenetics
Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to determine the processes by which diversity among species has been achieved. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree. Molecular phylogenetics is one aspect of molecular systematics, a broader term that also includes the use of molecular data in taxonomy and biogeography. Molecular phylogenetics and molecular evolution correlate. Molecular evolution is the process of selective changes (mutations) at a molecular level (genes, proteins, etc.) throughout various branches in the tree of life (evolution). Molecular phylogenetics makes inferences of the evolutionary relationships that arise due to molecular evolution and results in the construction of a phylogenetic tree. History The theoretical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheilanthes
''Cheilanthes'', commonly known as lip ferns, is a genus of about 180 species of rock-dwelling ferns with a cosmopolitan distribution in warm, dry, rocky regions, often growing in small crevices high up on cliffs. Most are small, sturdy and evergreen. The leaves, often densely covered in trichomes, spring directly from the rootstocks. Many of them are desert ferns, curling up during dry times and reviving with the coming of moisture. At the ends of veins sporangia, or spore-bearing structures, are protected by leaf margins, which curl over them. Taxonomy The genus name is derived from the Greek words χεῖλος (''cheilos''), meaning "lip," and ἄνθος (''anthos''), meaning "flower." ''Cheilanthes'' as traditionally circumscribed is now known to be highly paraphyletic, comprising at least four generically separate groups. The type species, '' C. micropteris'', is most closely allied to the genera '' Aleuritopteris'' and ''Sinopteris'' (Schuettpelz ''et al.''). In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notholaena
''Notholaena'' (from Ancient Greek νόθο(ς) + χλαῖνα), cloak fern, is a genus of ferns in the Cheilanthoideae subfamily of the Pteridaceae. Ferns of this genus are mostly epipetric (growing on rock) or occurring in coarse, gravelly soils, and are most abundant and diverse in the mountain ranges of warm arid or semiarid regions. They typically have a creeping or erect rhizome and leaves that are pinnatifid to pinnate-pinnatifid with marginal sori protected by a false indusium formed from the reflexed margin of the leaf. Members of ''Notholaena'' also have a coating of whitish or yellowish farina (a powdery secretion that prevents desiccation) on the surfaces of the leaves. The farina is often limited to the abaxial (lower) leaf surface, but may occur on the adaxial (upper) leaf surface as well. Members of the related Pentagramma genus have a similar lower leaf-surface farina. The similar genus '' Argyrochosma'' also has farinose leaves, but in that genus the ult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Description
A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have been described previously or are related. In order for species to be validly described, they need to follow guidelines established over time. Zoological naming requires adherence to the ICZN code, plants, the ICN, viruses ICTV, and so on. The species description often contains photographs or other illustrations of type material along with a note on where they are deposited. The publication in which the species is described gives the new species a formal scientific name. Some 1.9 million species have been identified and described, out of some 8.7 million that may actually exist. Millions more have become extinct throughout the existence of life on Earth. Naming process A name of a new species becomes valid (available in zo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cape Of Good Hope
The Cape of Good Hope ( af, Kaap die Goeie Hoop ) ;''Kaap'' in isolation: pt, Cabo da Boa Esperança is a rocky headland on the Atlantic coast of the Cape Peninsula in South Africa. A common misconception is that the Cape of Good Hope is the southern tip of Africa, based on the misbelief that the Cape was the dividing point between the Atlantic and Indian oceans, and have nothing to do with north or south. In fact, by looking at a map, the southernmost point of Africa is Cape Agulhas about to the east-southeast. The currents of the two oceans meet at the point where the warm-water Agulhas current meets the cold-water Benguela current and turns back on itself. That oceanic meeting point fluctuates between Cape Agulhas and Cape Point (about east of the Cape of Good Hope). When following the western side of the African coastline from the equator, however, the Cape of Good Hope marks the point where a ship begins to travel more eastward than southward. Thus, the firs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheilanthes Contracta
''Cheilanthes'', commonly known as lip ferns, is a genus of about 180 species of rock-dwelling ferns with a cosmopolitan distribution in warm, dry, rocky regions, often growing in small crevices high up on cliffs. Most are small, sturdy and evergreen. The leaves, often densely covered in trichomes, spring directly from the rootstocks. Many of them are desert ferns, curling up during dry times and reviving with the coming of moisture. At the ends of veins sporangia, or spore-bearing structures, are protected by leaf margins, which curl over them. Taxonomy The genus name is derived from the Greek words χεῖλος (''cheilos''), meaning "lip," and ἄνθος (''anthos''), meaning "flower." ''Cheilanthes'' as traditionally circumscribed is now known to be highly paraphyletic, comprising at least four generically separate groups. The type species, '' C. micropteris'', is most closely allied to the genera ''Aleuritopteris'' and '' Sinopteris'' (Schuettpelz ''et al.''). In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
