A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. Lichens are important actors in nutrient cycling and act as producers which many higher trophic feeders feed on, such as reindeer, gastropods, nematodes, mites, and springtails. 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.
The Cladoniaceae are a family of lichenized fungi in the order Lecanorales. It is one of the largest families of lichen-forming fungi, with about 560 species distributed amongst 17 genera. The reindeer moss and cup lichens (Cladonia) belong to this family. The latter genus, which comprises about 500 species, forms a major part of the diet of large mammals in taiga and tundra ecosystems. Many Cladoniaceae lichens grow on soil, but other can use decaying wood, tree trunks, and, in a few instances, rocks as their substrate. They grow in places with high humidity, and cannot tolerate aridity.
Xanthoria parietina is a foliose lichen in the family Teloschistaceae. It has wide distribution, and many common names such as common orange lichen, yellow scale, maritime sunburst lichen and shore lichen. It can be found near the shore on rocks or walls, and also on inland rocks, walls, or tree bark. It was chosen as a model organism for genomic sequencing by the US Department of Energy Joint Genome Institute (JGI).
Chrysothrix candelaris, commonly known as the mustard powder lichen or gold dust lichen, is a species of leprose (powdery) lichen in the family Chrysothricaceae. It typically grows on tree bark, although it has also been recorded growing on rock. It does not show ascocarps or other reproductive structures, belonging to the group commonly known as the 'Fungi or lichens imperfecti' in the UK.
Verrucariaceae is a family of lichens and a few non-lichenised fungi in the order Verrucariales. The lichens have a wide variety of thallus forms, from crustose (crust-like) to foliose (bushy) and squamulose (scaly). Most of them grow on land, some in freshwater and a few in the sea. Many are free-living but there are some species that are parasites on other lichens, while one marine species always lives together with a leafy green alga.
Vulpicida is a genus of lichenized fungi in the family Parmeliaceae. Circumscribed in 1993 to contain species formerly placed in Cetraria, the genus is widespread in Arctic to northern temperate regions, and contains six species. The genus is characterized by the presence of the secondary metabolites pulvinic acid and vulpinic acid, compounds that when combined with usnic acid, give the species their characteristic yellow and green colors.
Acarospora flavisparsa is a species of lichen in the family Acarosporaceae. Found in Portugal and Spain, it was described as new to science in 2011. The lichen grows on acidic rock walls in inland areas.
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.
Lecanora muralis(Protoparmeliopsis muralis) is a waxy looking, pale yellowish green crustose lichen that usually grows in rosettes radiating from a center (placodioid) filled with disc-like yellowish-tan fruiting bodies (apothecia). It grows all over the world. It is extremely variable in its characteristics as a single taxon, and may represent a complex of species. The fruiting body parts have rims of tissue similar to that of the main nonfruiting body (thallus), which is called being lecanorine. It is paler and greener than L. mellea, and more yellow than L. sierrae. In California, it may be the most common member of the Lecanora genus found growing on rocks (saxicolous).
Candelariella vitellina is a common and widespread green-yellow to orange-yellow crustose areolate lichen that grows on rock, wood, and bark, all over the world. It grows on non-calcareous rock, wood, and bark.
Pyxine subcinerea is a species of foliose lichen in the family Caliciaceae. It has a pantropical distribution, and typically grows on bark, but less commonly on rocks. The lichen is characterised by its yellow medulla, soralia on the margins on the lobes that make up the thallus, and the presence of the chemical lichexanthone in the cortex.
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.
Punctelia reddenda is a widely distributed species of foliose lichen in the family Parmeliaceae. It occurs in Africa, Europe, North America, and South America, where it grows on bark and on rock.
Punctelia graminicola is a species of foliose (leafy) lichen in the family Parmeliaceae. It grows on rocks, and, less frequently, on bark in North America, South America, and East Africa. It has a blue-grey thallus measuring up to about 15 cm (6 in), covered with tiny pores called pseudocyphellae. Sometimes the lichen forms small lobes that project out from the surface. Fruiting bodies are uncommon in this species; if present, they resemble small cups with a brown internal disc measuring 3–10 mm (0.1–0.4 in) in diameter. A lookalike species, Punctelia hypoleucites, is not readily distinguishable from Punctelia graminicola by appearance or habitat alone; these species can only be reliably differentiated by examining the length of their conidia.
Lichenomphalia tasmanica is a species of basidiolichen in the family Hygrophoraceae. It is found in Tasmania, Australia. It has a bright scaley thallus that grows like a green crust on rich soil between rocks. Occasionally. the lichen produces small, bright yellow-orange mushroom-like fruiting bodies.
Buellia lobata is a species of terricolous (soil-dwelling) lichen in the family Caliciaceae. Found in Australia, it was formally described as a new species in 2001 by lichenologists Ulrike Trinkaus and John Elix. The type specimen was collected in Blanchetown ; here, in a parking area after the bridge, on the east side of the Murray River, the lichen was found growing on soil. It has also been recorded from Western Australia. The lichen occurs on calcareous soil in mallee, often with other terricolous lichens including species of Endocarpon, Toninia, Eremastriella crystallifera, Fulgensia bracteata, and Psora decipiens. Secondary compounds that occur in the lichen include arthothelin and thuringione as major components, and minor amounts of 4,5-dichloronorlichexanthone and thiophanic acid. The species epithet lobata refers to the distinct lobes that comprise the thallus.
Pulchrocladia retipora, commonly known as the coral lichen, is a species of fruticose lichen in the family Cladoniaceae. Found predominantly in Australasia, its habitats range from the Australian Capital Territory to New Zealand's North and South Islands, and even the Pacific region of New Caledonia, where it grows in coastal and alpine heathlands. The lichen features coral-like branches and subbranches with numerous intricate, netlike perforations. It is known by multiple names, with some sources referring to it by its synonym Cladia retipora, or the common name lace lichen.
Solorina crocea, commonly known as the orange chocolate chip lichen, is a species of terricolous (ground-dwelling) and foliose (leafy) lichen in the family Peltigeraceae. The lichen, which was first formally described by Carl Linnaeus in 1753, has an arctic–alpine and circumpolar distribution and occurs in Asia, Europe, North America, and New Zealand. It generally grows on the bare ground in sandy soils, often in moist soil near snow patches or seepage areas. Although several forms and varieties of the lichen have been proposed in its history, these are not considered to have any independent taxonomic significance.
Crocodia is a genus of foliose lichens in the family Peltigeraceae. It has eight species. The genus has a cosmopolitan distribution, although most species occur in temperate and tropical regions of the Southern Hemisphere. The main characteristics of the genus that separate it from its parent genus, Pseudocyphellaria, include a yellow medulla and yellow pseudocyphellae on the lower thallus surface.
