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Lecidea Toensbergii
''Lecidea toensbergii'' is a species of saxicolous (rock-dwelling), crustose lichen in the family Lecideaceae. Described as a new species in 2018, it has been documented from several locations in Norway and a single location in Sweden, where it grows in rocky alpine environments. Taxonomy The lichen was formally described as a news species in 2018 by the lichenologists Reidar Haugan and Einar Timdal. The type specimen of ''Lecidea toensbergii'' was collected by Haugan in the Møre og Romsdal region of Norway. It was found on the western slope of in Norddal, at an elevation of . This lichen was growing on siliceous rock within a late snow bed in a low alpine heath environment. The species epithet honours the Norwegian lichenologist Tor Tønsberg. '' Lecidea leucothallina'' is similar in appearance, but unlike ''L. toensbergii'', that species does not produce soredia. At the time of its original publication, ''L. toensbergii'' was the only sorediate species in the gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several examples, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN, the definitions of types are similar in intent but not identical in terminology or underlying concept. For example, the holotype for the butterfly '' Plebejus idas longinus'' is a preserved specimen of that subspecies, held by the Museum of Comparative Zoology at Harvard University. In botany, an isotype is a duplicate of the holotype, where holotype and isotypes are often pieces from the same individual plant or samples from the same gathering. A holotype is not necessaril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prothallus
A prothallus, or prothallium, (from Latin ''pro'' = forwards and Greek ''θαλλος'' (''thallos'') = twig) is usually the gametophyte stage in the life of a fern or other pteridophyte. Occasionally the term is also used to describe the young gametophyte of a liverwort or peat moss as well. In lichens it refers to the region of the thallus that is free of algae. The prothallus develops from a germinating spore. It is a short-lived and inconspicuous heart-shaped structure typically 2–5 millimeters wide, with a number of rhizoids (root-like hairs) growing underneath, and the sex organs: archegonium (female) and antheridium (male). Appearance varies quite a lot between species. Some are green and conduct photosynthesis while others are colorless and nourish themselves underground as saprotrophs. Alternation of generations Spore-bearing plants, like all plants, go through a life-cycle of alternation of generations. The fully grown sporophyte, what is commonly referred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boulder Field
A blockfieldWhittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984, pp. 66 and 190. . (also spelt block fieldLeser, Hartmut, ed. (2005). ''Wörterbuch Allgemeine Geographie'', 13th ed., dtv, Munich, pp. 107 and 221. . ), felsenmeer, boulder field or stone field is a surface covered by boulder- or block-sized angular rocks usually associated with alpine and subpolar climates and periglaciation. Blockfields differ from screes and talus slope in that blockfields do not apparently originate from mass wastings. They are believed to be formed by frost weathering below the surface. An alternative theory that modern blockfields may have originated from chemical weathering that occurred in the Neogene when the climate was relatively warmer. Following this thought the blockfields would then have been reworked by periglacial action. Most known blockfields are located in the northern hemisphere. Examples can be found in Abisko National Park in Sweden, Snowdo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overhang (rock Formation)
An overhang is a rock face or artificial climbing wall with a slope of more than 90°, i.e. it slopes beyond the vertical. Particularly severe overhangs that reach, or nearly reach, the horizontal, are referred to as a roof. In climbing, overhangs and especially roofs place special demands both in terms of technique and equipment as well as the constitution of the climber. With increasing steepness the loading on arm and hand muscles increases, because the feet can support less and less of the body weight. Rest points where the muscles can be relaxed, especially no-hands rests, are rarely found in overhangs. Climbing techniques to tackle overhangs include placing the body's centre of mass as close as possible to the rock and striving for the highest possible body tension. Many climbing techniques such as the foothook are almost exclusively used in overhangs and roofs. For a long time in Alpine climbing, roofs were almost always tacked using climbing aids. By contrast, in m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spot Test (lichen)
A spot test in lichenology is a spot analysis used to help identify lichens. It is performed by placing a drop of a chemical on different parts of the lichen and noting the colour change (or lack thereof) associated with application of the chemical. The tests are routinely encountered in dichotomous keys for lichen species, and they take advantage of the wide array of lichen products produced by lichens and their uniqueness among taxa. As such, spot tests reveal the presence or absence of chemicals in various parts of a lichen. They were first proposed by the botanist William Nylander in 1866. Three common spot tests use either 10% aqueous KOH solution (K test), saturated aqueous solution of bleaching powder or calcium hypochlorite (C test), or 5% alcoholic ''p''-phenylenediamine solution (P test). The colour changes occur due to presence of particular secondary metabolites in the lichen. There are several other less frequently used spot tests of more limited use that are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thin-layer Chromatography
Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. Thin-layer chromatography is performed on a sheet of an inert substrate such as glass, plastic, or aluminium foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide (alumina), or cellulose. This layer of adsorbent is known as the stationary phase. After the sample has been applied on the plate, a solvent or solvent mixture (known as the mobile phase) is drawn up the plate via capillary action. Because different analytes ascend the TLC plate at different rates, separation is achieved. It may be performed on the analytical scale as a means of monitoring the progress of a reaction, or on the preparative scale to purify small amounts of a compound. TLC is an analytical tool widely used because of its simplicity, relative low cost, high sensitivity, and speed of separation. TLC functions on the same principle as all chromatography: a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conidiomata
Conidiomata (singular: Conidioma) are blister-like fruiting structures produced by a specific type of fungus called a coelomycete. They are formed as a means of dispersing asexual spores call conidia, which they accomplish by creating the blister-like formations which then rupture to release the contained spores. Structure Conidiomata mainly consist of a mass of densely packed hypha which develops below the surface of the host cuticle, and the fungus may or may not use some of the host’s own tissue to construct the structure. Development of these structures can either occur just below the cuticle or below the epidermal layer of the tissue. Formation on the differing levels is dependent upon the type of conidiomata being formed. Five types of conidioma have been found and are classified as acervuli, pycnidia, sporodochia, synnemata and corenima. Types Acervuli Acervuli is one of the two major groups of conidiomata (the other being pycnidia). Conidiomata of this type form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellipsoid
An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a 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 is either an ellipse, or is empty, or is reduced to a single point (this explains the name, meaning "ellipse-like"). It is bounded, which means that it may be enclosed in a sufficiently large sphere. An ellipsoid has three pairwise perpendicular axes of symmetry which intersect at a 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 axes'', or simply axes of the ellipsoid. If the three axes have different lengths, the figure is a triaxial ellipsoi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amyloid (mycology)
In mycology a tissue or feature is said to be amyloid if it has a positive amyloid reaction when subjected to a crude chemical test using iodine as an ingredient of either Melzer's reagent or Lugol's solution, producing a blue to blue-black staining. The term "amyloid" is derived from the Latin ''amyloideus'' ("starch-like"). It refers to the fact that starch gives a similar reaction, also called an amyloid reaction. The test can be on microscopic features, such as spore walls or hyphal walls, or the apical apparatus or entire ascus wall of an ascus, or be a macroscopic reaction on tissue where a drop of the reagent is applied. Negative reactions, called inamyloid or nonamyloid, are for structures that remain pale yellow-brown or clear. A reaction producing a deep reddish to reddish-brown staining is either termed a dextrinoid reaction (pseudoamyloid is a synonym) or a hemiamyloid reaction. Melzer's reagent reactions Hemiamyloidity Hemiamyloidity in mycology refers to a specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascus
An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or species can occur in numbers of one (e.g. '' Monosporascus cannonballus''), two, four, or multiples of four. In a few cases, the ascospores can bud off conidia that may fill the asci (e.g. '' Tympanis'') with hundreds of conidia, or the ascospores may fragment, e.g. some '' Cordyceps'', also filling the asci with smaller cells. Ascospores are nonmotile, usually single celled, but not infrequently may be coenocytic (lacking a septum), and in some cases coenocytic in multiple planes. Mitotic divisions within the developing spores populate each resulting cell in septate ascospores with nuclei. The term ocular chamber, or oculus, refers to the epiplasm (the portion of cytoplasm not used in ascospore formation) that is surrounded by the "bou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia ( basidiomycetes) or paraphyses ( ascomycetes). Cystidia are often important for microscopic identification. The subhymenium consists of the supportive hyphae from which the cells of the hymenium grow, beneath which is the hymenophoral trama, the hyphae that make up the mass of the hymenophore. The position of the hymenium is traditionally the first characteristic used in the classification and identification of mushrooms. Below are some examples of the diverse types which exist among the macroscopic Basidiomycota and Ascomycota. * In agarics, the hymenium is on the vertical faces of the gills. * In boletes and polypores, it is in a spongy mass of downward-pointing tubes. * In puffb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
