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Melanelixia Villosella
''Melanelixia'' is a genus of foliose lichens in the family Parmeliaceae. It contains 15 Northern Hemisphere species that grow on bark or on wood. The genus is characterized by a pored or fenestrate epicortex (a thin homogeneous polysaccharide layer on the surface of the cortex), and the production of lecanoric acid as the primary chemical constituent of the medulla. ''Melanelixia'' was circumscribed in 2004 as a segregate of the related genus '' Melanelia''. Taxonomy ''Melanelixia'' was circumscribed in 2004 as a segregate of the genus '' Melanelia''. ''Melanelixia'' originally contained eight species, including the type, '' M. glabra''. The genus name combines ''Melanelia'' with the name of lichenologist John A. Elix, "for his immense contributions to lichen systematics and chemistry, especially in Parmeliaceae." Several species distributed in the Southern Hemisphere were removed from ''Melanelixia'' and transferred to the new genus '' Austromelanelixia'' in 2017. This gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanelixia Californica
''Melanelixia californica'', the California camouflage lichen, is a species of foliose lichen in the family Parmeliaceae. It was first described in 2010 after molecular studies revealed that what was thought to be the European species '' Melanelixia glabra'' in North America was actually a distinct species. The lichen forms olive-green, leaf-like growths up to across and is characterized by its sparse transparent surface hairs and disk-shaped fruiting bodies. It is found primarily in southern California, where it grows mainly on oak trees in Mediterranean climate zones at elevations ranging from , though it has also been reported from Oregon's Cascade–Siskiyou National Monument. Taxonomy ''Melanelixia californica'' was first scientifically described in 2010 by the lichenologists Ana Crespo and Pradeep Divakar. The species was previously considered part of '' Melanelixia glabra'' before molecular phylogenetics studies revealed it to be a distinct species. Analysis of nuclear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soredia
Soredia are common reproduction, reproductive structures of lichens. Lichens asexual reproduction, reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungus, fungal hyphae wrapped around cyanobacteria or green algae. These can be either scattered diffusely across the surface of the lichen's thallus, or produced in localized structures called soralia. Fungal hyphae make up the basic body structure of a lichen. The soredia are released through openings in the upper cortex of the lichen structure. After their release, the soredia disperse to establish the lichen in a new location. References Fungal morphology and anatomy Lichenology {{lichen-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depsidone
Depsidones (+ " depside" + "one") are chemical compounds that are sometimes found as secondary metabolites in lichens. They are esters that are both depsides and cyclic ethers. An example is norstictic acid Norstictic acid is a depsidone produced as a secondary metabolites in lichens. The compound contains both an aldehyde carbonyl group and an adjacent hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical fo .... References {{reflist Biochemistry Carboxylate esters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitric Acid
Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most commercially available nitric acid has a concentration of 68% in water. When the solution contains more than 86% , it is referred to as ''fuming nitric acid''. Depending on the amount of nitrogen dioxide present, fuming nitric acid is further characterized as red fuming nitric acid at concentrations above 86%, or white fuming nitric acid at concentrations above 95%. Nitric acid is the primary reagent used for nitration – the addition of a nitro group, typically to an organic molecule. While some resulting nitro compounds are shock- and thermally-sensitive explosives, a few are stable enough to be used in munitions and demolition, while others are still more stable and used as synthetic dyes and medicines (e.g. metronidazole). Nitric acid is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium
Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, which is easily removed to create cation, an ion with a positive charge (which combines with anions to form salts). In nature, potassium occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-flame color, colored flame. It is found dissolved in seawater (which is 0.04% potassium by weight), and occurs in many minerals such as orthoclase, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Pigment
A biological pigment, also known simply as a pigment or biochrome, is a substance produced by living organisms that have a color resulting from selective Absorption (electromagnetic radiation), color absorption. Biological pigments include plant pigments and flower pigments. Many biological structures, such as skin, eyes, feathers, fur and hair contain pigments such as melanin in specialized cells called chromatophores. In some species, pigments accrue over very long periods during an individual's lifespan. Pigment color differs from structural color in that it is the same for all viewing angles, whereas structural color is the result of selective Reflection (physics), reflection or iridescence, usually because of multilayer structures. For example, butterfly wings typically contain structural color, although many butterflies have cells that contain pigment as well. Biological pigments See conjugated systems for electron bond chemistry that causes these molecules to have pigm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleurosticta
''Pleurosticta'' is a small genus of foliose lichens belonging to the family Parmeliaceae. It has two species. Taxonomy The genus was circumscribed by mycologist Franz Petrak in 1931, with ''Pleurosticta lichenicola'' assigned as the type species. This is now known as a synonym of '' P. acetabulum''. The genus name fell into disuse when its species were transferred to '' Melanelia''. In 1980, Theodore Esslinger proposed conserving the name ''Melanelia'' for these species. However, H. Thorsten Lumbsch, Hans Kothe, and Jack Elix argued against this in 1988, choosing instead to resurrect ''Pleurosticta''. Their decision was based on detailed morphological, chemical, and geographical studies which demonstrated that ''P. acetabulum'' and '' P. koflerae'' formed a distinct group warranting recognition at the generic level. The resurrection was supported by several distinctive characteristics that set these species apart from other members of the "brown Parmeliae", i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometre
The micrometre (English in the Commonwealth of Nations, Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System of Units (SI) equalling (SI standard prefix "micro-" = ); that is, one millionth of a metre (or one thousandth of a millimetre, , or about ). The nearest smaller common SI Unit, SI unit is the nanometre, equivalent to one thousandth of a micrometre, one millionth of a millimetre or one billionth of a metre (). The micrometre is a common unit of measurement for wavelengths of infrared radiation as well as sizes of biological cell (biology), cells and bacteria, and for grading wool by the diameter of the fibres. The width of a single human hair ranges from approximately 20 to . Examples Between 1 μm and 10 μm: * 1–10 μm – length of a typical bacterium * 3–8 μm – width of str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellipsoid
An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathematics), surface that may be defined as the zero set of a polynomial of degree two in three variables. Among quadric surfaces, an ellipsoid is characterized by either of the two following properties. Every planar Cross section (geometry), cross section is either an ellipse, or is empty, or is reduced to a single point (this explains the name, meaning "ellipse-like"). It is Bounded set, bounded, which means that it may be enclosed in a sufficiently large sphere. An ellipsoid has three pairwise perpendicular Rotational symmetry, axes of symmetry which intersect at a Central symmetry, center of symmetry, called the center of the ellipsoid. The line segments that are delimited on the axes of symmetry by the ellipsoid are called the ''principal ax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascospore
In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse Division (botany), division of fungi. After two parental cell nucleus, nuclei fuse, the ascus undergoes meiosis (halving of genetic material) followed by a mitosis (cell division), ordinarily producing eight genetically distinct haploid spores; most yeasts stop at four ascospores, whereas some moulds carry out extra post-meiotic divisions to yield dozens. Many asci build turgor, internal pressure and shoot their spores clear of the calm boundary layer, thin layer of still air enveloping the fruit body, whereas subterranean truffles depend on animals for biological dispersal, dispersal. Ontogeny, Development shapes both form and endurance of ascospores. A hook-shaped crozier aligns the paired nuclei; a double-biological membrane, membrane system then parcels each daughter nucleus, and successive wall layers of β-glucan, chitosan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apothecia
An ascocarp, or ascoma (: ascomata), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are most commonly bowl-shaped (apothecia) but may take on a spherical or flask-like form that has a pore opening to release spores (perithecia) or no opening (cleistothecia). Classification The ascocarp is classified according to its placement (in ways not fundamental to the basic taxonomy). It is called ''epigeous'' if it grows above ground, as with the morels, while underground ascocarps, such as truffles, are termed ''hypogeous''. The structure enclosing the hymenium is divided into the types described below (apothecium, cleistothecium, etc.) and this character ''is'' important for the taxonomic classification of the fungus. Apothecia can be relatively large and fleshy, whereas the others are microscopic—about the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isolichenan
Isolichenan, also known as isolichenin, is a cold-water-soluble α-glucan occurring in certain species of lichens. This lichen product was first isolated as a component of an extract of Iceland moss in 1813, along with lichenin. After further analysis and characterization of the individual components of the extract, isolichenan was named in 1881. It is the first α-glucan to be described from lichens. The presence of isolichenan in the cell walls is a defining characteristic in several genera of the lichen family Parmeliaceae. Although most prevalent in that family, it has also been isolated from members of the families Ramalinaceae, Stereocaulaceae, Roccellaceae, and Cladoniaceae. Experimental studies have shown that isolichenan is produced only when the two lichen components – fungus and alga – are growing together, not when grown separately. The biological function of isolichenan in the lichen thallus is unknown. Early studies Isolichenan was first isolated from ''Cetra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
