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Charophyta
Charophyta () is a group of freshwater green algae, called charophytes (), sometimes treated as a division, yet also as a superdivision or an unranked clade. The terrestrial plants, the Embryophyta emerged within Charophyta, possibly from terrestrial unicellular charophytes, with the class Zygnematophyceae as a sister group. The clade Streptophyta may be formed by placing Embryophyta within the Charophyta. The Embryophyta may already be included in the Charophyta, in which case it is a synonym of the Streptophyta. The sister group of the charophytes are the Chlorophyta. In some charophyte groups, such as the Zygnematophyceae or conjugating green algae, flagella are absent and sexual reproduction does not involve free-swimming flagellate sperm. Flagellate sperm, however, are found in stoneworts ( Charales) and Coleochaetales, orders of parenchymatous charophytes that are the closest relatives of the land plants, where flagellate sperm are also present in all except the coni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streptophyta
Streptophyta (), informally the streptophytes (, from the Greek ''strepto'' 'twisted', for the morphology of the sperm of some members), is a clade of plants. The composition of the clade varies considerably between authors, but the definition employed here includes land plants and all green algae except the Chlorophyta and the more basal Prasinodermophyta. Classifications The composition of Streptophyta and similar groups (Streptophytina, Charophyta) varies in each classification. Some authors are more restrictive, including only the Charales and Embryophyta (e.g., Streptophyta Jeffrey 1967; Adl et al. 2012, Streptophytina Lewis & McCourt 2004), others include more groups (e.g., Charophyta Lewis & McCourt 2004; Karol et al. 2009; Adl et al. 2012, Streptophyta Bremer, 1985; de Reviers 2002; Leliaert et al. 2012, Streptobionta Kenrick & Crane 1997; some authors use this broader definition, but exclude the Embryophyta, e.g., Charophyta Cavalier-Smith 1993; Leliaert et al. 2012, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryophyta
The Embryophyta (), or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embryophytes () have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of green algae as sister of the Zygnematophyceae. The Embryophyta consist of the bryophytes plus the polysporangiophytes. Living embryophytes therefore include hornworts, liverworts, mosses, lycophytes, ferns, gymnosperms and flowering plants. The land plants have diplobiontic life cycles and it is accepted now that they emerged from freshwater, multi-celled algae. The embryophytes are informally called land plants because they live primarily in terrestrial habitats (with exceptional members who evolved to live once again in aquatic habitats), while the related green algae are primarily aquatic. Embryophytes are complex multicellular eukaryotes with specialized reproductive organs. The name derives from their innovative characteristic of nurturing the you ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coleochaetales
Coleochaetaceae is a family of algae. It is the only family in the Coleochaetales, an order of parenchymous charophyte algae, that includes some of the closest multicellular relatives of land plants. They questionably include the fossil genus ''Parka A parka or anorak is a type of coat with a hood, often lined with fur or faux fur. This kind of garment is a staple of Inuit clothing, traditionally made from caribou or seal skin, for hunting and kayaking in the frigid Arctic. Some Inuit ...''. References Charophyta Green algae orders {{alga-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walter Migula
Emil Friedrich August Walter (or Walther) Migula (born 1863 in Żyrowa, Poland; died 1938 in Eisenach, Germany) was a Poland-born German botanist. In 1890, he was habilitated for botany at Karlsruhe Institute of Technology, where he spent several years as a professor. At Karlsruhe, he also worked in the bacteriology department of the Food Research Institute. He was Professor of Botany at the research academy at Eisenach. He published many articles on the subjects of cryptogamic botany, bacteriology, and plant physiology. He is remembered for describing the bacterial genus ''Pseudomonas'', and for publication of ''Kryptogamen-Flora von Deutschland, Deutsch-Österreich und der Schweiz'' ryptogamic Flora of Germany, Austria, and Switzerland">Austria.html" ;"title="ryptogamic Flora of Germany, Austria">ryptogamic Flora of Germany, Austria, and Switzerland], a work connected with Otto Wilhelm Thomé's ''Flora von Deutschland'' [Plants of Germany]. Other significant works by Migula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oogonia
An oogonium (plural oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in large numbers by mitosis early in fetal development from primordial germ cells. In humans they start to develop between weeks 4 and 8 and are present in the fetus between weeks 5 and 30. Structure Normal oogonia in human ovaries are spherical or ovoid in shape and are found amongst neighboring somatic cells and oocytes at different phases of development. Oogonia can be distinguished from neighboring somatic cells, under an electron microscope, by observing their nuclei. Oogonial nuclei contain randomly dispersed fibrillar and granular material whereas the somatic cells have a more condensed nucleus that creates a darker outline under the microscope. Oogonial nuclei also contain dense prominent nucleoli. The chromosomal material in the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexachara
''Hexachara'' is a genus of fossil charophyte (aquatic green alga) that is likely to have formed meadows within sheltered oligohaline reaches of lakes. Etymology ''Hexachara'' is derived from Greek "hex", meaning six, a reference to the hexaradial symmetry; chara, referring to membership of the Charales. The specific name ''setacea'' is derived from Latin "seta", a bristle, that is a reference to the thin pointed branchlet. The specific name ''riniensis'' is derived from the Xhosa word ''Rini'', which is a traditional name for Grahamstown/ Makhanda and the surrounding valley. Description The whorls of branches are arranged in a hexaradial symmetrical manner. In ''Hexachara'' each node produces a whorl of six laterals, and oogonia are produced on each lateral. The known species to date include ''Hexachara setacea'' and ''Hexachara riniensis'' that have been recovered from a carbonaceous shale near the top of the Late Devonian, Famennian, Witpoort Formation (Witteberg Group) ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octochara
''Octochara'' is a genus of fossil charophyte (aquatic green alga) from the Famennian (Late Devonian). It is one of two genera of charophyte described from the Waterloo Farm lagerstätte in southern Africa. It and ''Hexachara'', from the same locality provide the oldest record of reconstruct able charophytes with in situ oogonia. ''Octochara'' is derived from a Greek word "octo", meaning eight, a reference to the octoradial symmetry, and "chara", referring to membership of the Charales. In ''Octochara'', a whorl of eight laterals are borne at each node. Each lateral is branched to produce four secondary branches and bears an oogonium An oogonium (plural oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in l .... Two species of ''Octochara'' have been described, ''Octochara crassa'' and ''Octochara gracilis''. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waterloo Farm Lagerstätte
The Waterloo Farm lagerstätte is a Famennian lagerstätte in South Africa that constitutes the only known record of a near-polar Devonian coastal ecosystem. History and discovery The Waterloo Farm Lagerstätte is an approximately 360 million year old Famennian (latest Devonian) fossil-rich locality of the Witpoort Formation (Witteberg Group, Cape Supergroup) in Makhanda (former Grahamstown) within the Eastern Cape Province, South Africa. Before it’s discovery very little was known of life during the Famennian (see Late Devonian extinction) in what is now southern Africa . This is largely due to the fact that fossils in the Witpoort Formation generally occur in black anaerobically deposited metashale that rapidly degrades near surface and is therefore rarely seen in natural outcrop. As is the case with many other scientific discoveries, the discovery of Waterloo Farm was accidental. Uprisings against the apartheid system in South Africa had by the mid-1980s escalated to vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynie Chert
The Rhynie chert is a Lower Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness (a Lagerstätte). It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is located some 700 m away. The Rhynie chert contains exceptionally preserved plant, fungus, lichen and animal material preserved in place by an overlying volcanic deposit. The bulk of the Devonian fossil bed consists of primitive plants (which had water-conducting cells and sporangia, but no true leaves), along with arthropods, lichens, algae and fungi. This fossil bed is remarkable for two reasons. First, the age of the site ( Pragian, Early Devonian, formed about ) places it at an early stage in the colonisation of land. Second, these cherts are famous for their exceptional state of ultrastructural preservation, with individual cell walls easily visible in polished specimens. Stomata have been counted and lignin remnants detected in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiosperm
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants that produce their seeds enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta (). Like gymnosperms, angiosperms are seed-producing plants. They are distinguished from gymnosperms by characteristics including flowers, endosperm within their seeds, and the production of fruits that contain the seeds. The ancestors of flowering plants diverged from the common ancestor of all living gymnosperms before the end of the Carboniferous, over 300 million years ago. The closest fossil relatives of flowering plants are uncertain and contentious. The earliest angiosperm fossils are in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinophyta
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews.Campbell, Reece, "Phylum Coniferophyta". Biology. 7th. 2005. Print. P. 595 As of 1998, the division Pinophyta was estimated to contain eight families, 68 genera, and 629 living species. Although the total number of species is relatively small, conifers are ecologically important. They are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere, but also in similar cool climates in mountains further south. Boreal conifers have many wintertime adaptat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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