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Punctelia Caseana
''Punctelia caseana'' is a species of foliose lichen in the family Parmeliaceae. Its range covers eastern North America, extending south to central and northern Mexico, where it grows on the bark of many species of hardwood and conifer trees. Taxonomy ''Punctelia caseana'' was described as a new species in 2010 by lichenologists James Lendemer and Brendan Hodkinson. The type was collected in the Nature Conservancy reserve in Atlantic County, New Jersey. The specific epithet ''caseana'' honors Martha A. Case, who was an undergraduate professor of Hodkinson and encouraged his interest in lichenology. Description The color of the upper surface of the thallus of ''Punctelia caseana'' is grey-blue, while the undersurface is pale to off-white, sometimes light brown. The size of the thallus is quite variable, depending largely on the microhabitat conditions. There are many soralia, which are mostly located along the margins of the lobes. The soredia are coarse and large. Ascospores p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delmarva Peninsula
The Delmarva Peninsula, or simply Delmarva, is a large peninsula and proposed state on the East Coast of the United States, occupied by the vast majority of the state of Delaware and parts of the Eastern Shore regions of Maryland and Virginia. The peninsula is long. In width, it ranges from near its center, to at the isthmus on its northern edge, to less near its southern tip of Cape Charles. It is bordered by the Chesapeake Bay on the west, Pocomoke Sound on the southwest, and the Delaware River, Delaware Bay, and the Atlantic Ocean on the east. Etymology In older sources, the peninsula between Delaware Bay and Chesapeake Bay was referred to variously as the Delaware and Chesapeake Peninsula or simply the Chesapeake Peninsula. The toponym ''Delmarva'' is a clipped compound of Delaware, Maryland, and Virginia ( official abbreviation ''VA''), which in turn was modeled after Delmar, a border town named after two of those states. While Delmar was founded and named in 1859 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a 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 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 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 . The longest human chromosome, chromosome 1, is approximately in length. Examples Between 1 μm and 10 μm: * 1–10 μm – length of a typical bacterium * 3–8 μm � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Punctelia Perrituculata
''Punctelia'' is a genus of foliose lichens belonging to the large family Parmeliaceae. The genus, which contains about 50 species, was segregated from genus ''Parmelia'' in 1982. Characteristics that define ''Punctelia'' include the presence of hook-like to thread-like conidia (asexual spores), simple rhizines (root-like structures that attach the lichen thallus to its substrate), and point-like pseudocyphellae (tiny pores on the thallus surface that facilitate gas exchange). It is this last feature that is alluded to in the vernacular names speckled shield lichens or speckleback lichens. ''Punctelia'' lichens grow on bark, wood, and rocks. The genus is cosmopolitan, occurring on all continents but Antarctica. Species are found in temperate to subtropical locations. ''Punctelia'' has centres of distribution in the Neotropics and Africa; about half of the known species occur in South America. The photobiont partners of ''Punctelia'' are green algae in the genus ''Trebouxia''. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isidia
An isidium is a vegetative reproductive structure present in some lichens. Isidia are outgrowths of the thallus surface, and are corticated (i.e., containing the outermost layer of the thallus), usually with a columnar structure, and consisting of both fungal hyphae (the mycobiont) and algal cells (the photobiont). They are fragile structures and may break off and be distributed by wind, animals, and splashing raindrops. In terms of structure, isidia may be described as warty, cylindrical, clavate (club-shaped), scale-like, coralloid (coral-shaped), simple, or branched. Examples of isidiate lichens include members of the genera ''Parmotrema ''Parmotrema'' is a genus of lichen belonging to the family Parmeliaceae. It is a large genus, containing an estimated 300 species, with a centre of diversity in subtropical regions of South America and the Pacific Islands. Members of the ge ...'' and '' Peltigera''. See also Soredium References External linksAscomycetes glo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Punctelia Rudecta
''Punctelia rudecta'', commonly known as the rough speckled shield or the speckleback lichen, is a North American species of foliose lichen in the family Parmeliaceae. This species can be readily identified by the light color of the thallus underside, the relatively large lobes at the edges of the thallus, and the tiny white pores present on the top of the thallus that are characteristic of the genus ''Punctelia''. The lichen is quite abundant and widespread in the eastern and southeastern United States, although it also occurs in Canada and northern Mexico, but is less common in these regions. The lichen usually grows on bark, and less commonly on shaded rocks. There are several lookalike ''Punctelia'' species; these can often be distinguished from ''P. rudecta'' by differences in distribution or in the nature of the reproductive structures present on the thallus. Although ''Punctelia rudecta'' was previously thought to have a much more expansive global distribution, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cortex (botany)
In botany, a cortex is an outer layer of a stem or root in a vascular plant, lying below the epidermis but outside of the vascular bundles. The cortex is composed mostly of large thin-walled parenchyma cells of the ground tissue system and shows little to no structural differentiation. The outer cortical cells often acquire irregularly thickened cell walls, and are called collenchyma cells. Plants Stems and branches In the three dimensional structure of herbaceous stems, the epidermis, cortex and vascular cambium form concentric cylinders around the inner cylindrical core of pith. Some of the outer cortical cells may contain chloroplasts, giving them a green color. They can therefore produce simple carbohydrates through photosynthesis. In woody plants, the cortex is located between the periderm (bark) and the vascular tissue (phloem, in particular). It is responsible for the transportation of materials into the central cylinder of the root through diffusion and may al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-Phenylenediamine
''p''-Phenylenediamine (PPD) is an organic compound with the formula C6H4(NH2)2. This derivative of aniline is a white solid, but samples can darken due to air oxidation. It is mainly used as a component of engineering polymers and composites like kevlar. It is also an ingredient in hair dyes and is occasionally used as a substitute for henna. Production PPD is produced via three routes. Most commonly, 4-nitrochlorobenzene is treated with ammonia and the resulting 4-nitroaniline is then hydrogenated: :ClC6H4NO2 + 2 NH3 → H2NC6H4NO2 + NH4Cl :H2NC6H4NO2 + 3 H2 → H2NC6H4NH2 + 2 H2O In the DuPont route, aniline is converted to diphenyltriazine, which is then converted by acid-catalysis to 4-aminoazobenzene. Hydrogenation of the latter affords PPD.Robert A. Smiley "Phenylene- and Toluenediamines" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2002, Wiley-VCH, Weinheim. Uses Precursor to polymers PPD is a precursor to aramid plastics and fibers such as K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hypochlorite
Sodium hypochlorite (commonly known in a dilute solution as bleach) is an inorganic chemical compound with the formula NaOCl (or NaClO), comprising a sodium cation () and a hypochlorite anion (or ). It may also be viewed as the sodium salt of hypochlorous acid. The anhydrous compound is unstable and may decompose explosively. It can be crystallized as a pentahydrate ·5, a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated. Sodium hypochlorite is most often encountered as a pale greenish-yellow dilute solution referred to as liquid bleach, which is a household chemical widely used (since the 18th century) as a disinfectant or a bleaching agent. In solution, the compound is unstable and easily decomposes, liberating chlorine, which is the active principle of such products. Sodium hypochlorite is the oldest and still most important chlorine-based bleach. Its corrosive properties, common availability, and reaction products make it a signif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Hydroxide
Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exploit its caustic nature and its reactivity toward acids. An estimated 700,000 to 800,000 tonnes were produced in 2005. KOH is noteworthy as the precursor to most soft and liquid soaps, as well as numerous potassium-containing chemicals. It is a white solid that is dangerously corrosive. Properties and structure KOH exhibits high thermal stability. Because of this high stability and relatively low melting point, it is often melt-cast as pellets or rods, forms that have low surface area and convenient handling properties. These pellets become tacky in air because KOH is hygroscopic. Most commercial samples are ca. 90% pure, the remainder being water and carbonates. Its dissolution in water is strongly exothermic. Concentrated aqueous so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lichen Spot Test
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 employ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lecanoric Acid
Lecanoric acid is a chemical produced by several species of lichen.ubChem - Lecanoric acid"> Lecanoric acid is classified as a polyphenol and a didepside and it functions as an antioxidant. The acid is named after the lichen ''Lecanora''. The acid has also been isolated from ''Usnea subvacata'', ''Parmotrema stuppuem'', ''Parmotrema tinctorum,'' ''Parmotrema grayana,'' Xanthoparmelia arida and Xanthoparmelia lecanorica ''Xanthoparmelia lecanorica'' is a foliose lichen that belongs to the genus ''Xanthoparmelia''. It is noted for being similar in appearance and has often been misidentified as ''Xanthoparmelia arida''. Description ''Xanthoparmelia lecanorica'' .... A related compound, 5-chlorolecanoric acid, is found in some species of '' Punctelia''. References {{Reflist Polyphenols Benzoic acids Benzoate esters Lichen products ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
