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Asterochloris Irregularis
''Asterochloris'' is a genus of green algae in the family Trebouxiophyceae. It is a common in lichen, occurring in the thalli of more than 20 lichen genera worldwide. ''Asterochloris'' is distinguishable from the morphologically similar genus ''Trebouxia'', primarily due to its deeply lobed chloroplast, the placement of the chloroplast along the cell's periphery before the initiation of zoospore or aplanospore formation, and its tendency to primarily reproduce asexually through the production of aplanospores. Taxonomy The genus was circumscribed in 1980 by Elisabeth Tschermak-Woess, with '' Asterochloris phycobiontica'' assigned as the type species. She differentiated it from the related genus ''Trebouxia'' by differences in chloroplast morphology. Later molecular research showed that ''Trebouxia'' was paraphyletic, and that some ''Trebouxia'' species were closely related to genus ''Asterochloris''. In 2010, Škaloud and Peksa proposed to split the genus ''Trebouxia'' and form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyletic
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic grouping (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term received currency during the debates of the 1960s and 1970s accompanying the rise of cladistics, having been coined by zoologist Willi Hennig to apply to well-known taxa like Reptilia (reptiles), which is paraphyletic with respect to birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tundra
In physical geography, a tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: #Arctic, Arctic, Alpine tundra, Alpine, and #Antarctic, Antarctic. Tundra vegetation is composed of dwarf shrubs, Cyperaceae, sedges, Poaceae, grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline. The tundra soil is rich in nitrogen and phosphorus. The soil also contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide in the permafrost, making the tundra soil a carbon sink. As global warming heats the ecosystem and causes soil thawing, the permafrost carbon cycle accelerates and releases much of these soil-contained greenhouse gases into the atmosphere, creating Climate change feedback, a feedback cycle t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereocaulaceae
The Stereocaulaceae are a family of lichen-forming fungi in the order Lecanorales. It contains five genera. Species of this family are widely distributed in temperate boreal and austral regions. Genera *'' Hertelidea'' – 6 spp. *''Lepraria ''Lepraria'' is a genus of leprose (powdery) crustose lichens that grows on its substrate like patches of granular, caked up, mealy dust grains.A taxonomic revision of the North American species of Lepraria s.l. that produce divaricatic acid, w ...'' – 86 spp. *'' Stereocaulon'' – 45 spp. *'' Squamarina'' – 4 spp. *'' Xyleborus'' – 2 spp. References * Lichen families Lecanoromycetes families Taxa named by François Fulgis Chevallier Taxa described in 1826 {{Lecanorales-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladoniaceae
The Cladoniaceae are a family of lichen-forming fungi in the order Lecanorales, comprising about 560 species distributed amongst 18 genera. This family is one of the largest among lichen-forming fungi and is globally distributed, from Arctic tundra to tropical rainforests, favouring humid environments while being intolerant of arid conditions. Molecular phylogenetics has significantly advanced the understanding of their complex taxonomic history, revealing intricate evolutionary relationships and leading to a refined classification. Notable members include reindeer moss and cup lichens of the genus '' Cladonia'', which consist of about 500 species and forms a significant part of the diet for large mammals in taiga and tundra ecosystems. A distinctive feature of many Cladoniaceae species is their dimorphic thallus: a scaly or crust-like form and a (shrub-like) secondary form known as a podetium or . These lichens typically grow on soil, decaying wood, or tree trunks, with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
