| Lecidella greenii | |
|---|---|
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Lecanorales |
| Family: | Lecanoraceae |
| Genus: | Lecidella |
| Species: | L. greenii |
| Binomial name | |
| Lecidella greenii U.Ruprecht & Türk (2011) | |
Lecidella greenii is a species of lichen in the family Lecanoraceae. Known from Antarctica, it was described as new to science in 2011. [1]
Lichenology is the branch of mycology that studies the lichens, symbiotic organisms made up of an intimate symbiotic association of a microscopic alga with a filamentous fungus.
A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. Lichens have properties different from those of their component organisms. They come in many colors, sizes, and forms and are sometimes plant-like, but are not plants. They may have tiny, leafless branches (fruticose); flat leaf-like structures (foliose); grow crust-like, adhering tightly to a surface (substrate) like a thick coat of paint (crustose); have a powder-like appearance (leprose); or other growth forms.
Cladonia rangiferina, also known as reindeer cup lichen, reindeer lichen or grey reindeer lichen, is a light-colored fruticose, cup lichen species in the family Cladoniaceae. It grows in both hot and cold climates in well-drained, open environments. Found primarily in areas of alpine tundra, it is extremely cold-hardy.
In archaeology, palaeontology, and geomorphology, lichenometry is a geomorphic method of geochronologic dating that uses lichen growth to determine the age of exposed rock, based on a presumed specific rate of increase in radial size over time. Measuring the diameter of the largest lichen of a species on a rock surface can therefore be used to determine the length of time the rock has been exposed. Lichen can be preserved on old rock faces for up to 10,000 years, providing the maximum age limit of the technique, though it is most accurate when applied to surfaces that have been exposed for less than 1,000 years. Lichenometry is especially useful for dating surfaces less than 500 years old, as radiocarbon dating techniques are less accurate over this period. The lichens most commonly used for lichenometry are those of the genera Rhizocarpon and Xanthoria. The measured growth rates of R. geographicum tends to fall within the range of 0.9–0.3 millimeter per year, depending on several factors, including the size of the lichen patch.
Parmelia is a genus of medium to large foliose lichens. It has a global distribution, extending from the Arctic to the Antarctic continent but concentrated in temperate regions. There are about 40 species in Parmelia. In recent decades, the once large genus Parmelia has been divided into a number of smaller genera according to thallus morphology and phylogenetic relatedness.
The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2700 species in 71 genera, it is the largest family of lichen-forming fungi. The most speciose genera in the family are the well-known groups: Xanthoparmelia, Usnea, Parmotrema, and Hypotrachyna.
The Arthoniales is the second largest order of mainly crustose lichens, but fruticose lichens are present as well. The order contains around 1500 species, while the largest order with lichenized fungi, the Lecanorales, contains more than 14000 species.
The Verrucariaceae are a family of mostly lichenised fungi in the order Verrucariales. The lichen-forming species, which comprise the vast majority of the family, have a wide variety of thallus forms, and include crustose (crust-like), foliose (bushy), and squamulose (scaly) representatives. Several characteristics of the spore-bearing structures, the ascomata, define the family, including their perithecioid form–more or less spherical or flask-shaped, with a single opening and otherwise completely enclosed by a wall. Squamulose members of the Verrucariaceae with simple ascospores, and without algae in the spore-bearing region are known as catapyrenioid lichens; there are more than 80 of these species. The family has several dozen lichenicolous (lichen-dwelling) examples, and a few genera that contain solely lichenicolous members. An unusually diverse variety of photobiont partners have been recorded, mostly green algae, but also brown algae and yellow-green algae.
Ramalina is a genus of greenish fruticose lichens that grow in the form of flattened, strap-like branches. Members of the genus are commonly called strap lichens or cartilage lichens. Apothecia are lecanorine.
Hypogymnia is a genus of foliose lichens in the family Parmeliaceae. They are commonly known as tube lichens, bone lichens, or pillow lichens. Most species lack rhizines that are otherwise common in members of the Parmeliaceae, and have swollen lobes that are usually hollow. The lichens usually grow on the bark and wood of coniferous trees.
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, simple rhizines, and point-like pseudocyphellae. It is this last feature that is alluded to in the vernacular names speckled shield lichens or speckleback lichens.
Dictyonema is a genus of mainly tropical basidiolichens in the family Hygrophoraceae.
Lepraria is a genus of leprose crustose lichens that grows on its substrate like patches of granular, caked up, mealy dust grains. Members of the genus are commonly called dust lichens. The main vegetative body (thallus) is made of patches of soredia. There are no known mechanisms for sexual reproduction, yet members of the genus continue to speciate. Some species can form marginal lobes and appear squamulose. Because of the morphological simplicity of the thallus and the absence of sexual structures, the composition of lichen products are important characters to distinguish between similar species in Lepraria.
André Aptroot is a Dutch mycologist and lichenologist.
Crustose lichens are lichens that form a crust which strongly adheres to the substrate, making separation from the substrate impossible without destruction. The basic structure of crustose lichens consists of a cortex layer, an algal layer, and a medulla. The upper cortex layer is differentiated and is usually pigmented. The algal layer lies beneath the cortex. The medulla fastens the lichen to the substrate and is made up of fungal hyphae. The surface of crustose lichens is characterized by branching cracks that periodically close in response to climatic variations such as alternate wetting and drying regimes.
A lichenicolous fungus is a parasitic fungus that only lives on lichen as the host. A lichenicolous fungus is not the same as the fungus that is the component of the lichen, which is known as a lichenized fungus. They are most commonly specific to a given fungus as the host, but they also include a wide range of pathogens, saprotrophs, and commensals. It is estimated there are 3000 species of lichenicolous fungi. More than 1800 species are already described among the Ascomycota and Basidiomycota. More than 95% of lichenicolous fungi described as of 2003 are ascomycetes, in 7 classes and 19 orders. Although basidiomycetes have less than 5% of lichenicolous lichen species, they represent 4 classes and 8 orders. Many lichenicolous species have yet to be assigned a phylogenetic position as of 2003.
Thomas Hawkes Nash III is an American lichenologist. His research is about the biology and ecology of lichens, and the effects of air pollution on plants and lichens. He is known as an authority on the family Parmeliaceae. During his long career at the Arizona State University, he helped develop the lichen herbarium into a world-class collection with over 100,000 specimens representing more than 5000 species. In 2010, the year of his retirement, he was awarded the Acharius Medal for lifetime achievements in lichenology, and the following year had a Festschrift published in his honor.
Helge Thorsten Lumbsch is a German-born lichenologist living in the United States. His research interests include the phylogeny, taxonomy, and phylogeography of lichen-forming fungi; lichen diversity; lichen chemistry and chemotaxonomy. He is the Associate Curator and Head of Cryptogams and Chair of the Department of Botany at the Field Museum of Natural History.
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.
Lichexanthone is an organic compound in the structural class of chemicals known as xanthones. Lichexanthone was first isolated and identified by Japanese chemists from a species of leafy lichen in the 1940s. The compound is known to occur in many lichens, and it is important in the taxonomy of species in several genera, such as Pertusaria and Pyxine. More than a dozen lichen species have a variation of the word lichexanthone incorporated as part of their binomial name. The presence of lichexanthone in lichens causes them to fluoresce a greenish-yellow colour under long-wavelength UV light; this feature is used to help identify some species. Lichexanthone is also found in several plants, and some species of fungi that do not form lichens.
 | This Lecanorales-related article is a stub. You can help Wikipedia by expanding it. |