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.
NVC community CG7 is one of the calcicolous grassland communities in the British National Vegetation Classification system. It is one of three short-sward communities associated with heavy grazing, within the lowland calcicolous grassland group, and is regarded as the eastern counterpart of "typical" chalk grassland.
Caloplaca is a lichen genus comprising a number of distinct species. Members of the genus are commonly called firedot lichen, jewel lichen. gold lichens, "orange lichens", but they are not always orange, as in the case of C. albovariegata. The distribution of this lichen genus is worldwide, extending from Antarctica to the high Arctic. It includes a portion of northern North America and the Russian High Arctic. There are about thirty species of Caloplaca in the flora of the British Isles.
Lecanora is a genus of lichen commonly called rim lichens. Lichens in the genus Squamarina are also called rim lichens. Members of the genus have roughly circular fruiting discs (apothecia) with rims that have photosynthetic tissue similar to that of the nonfruiting part of the lichen body (thallus). Other lichens with apothecia having margins made of thallus-like tissue are called lecanorine.
Acarospora is a genus of mostly lichen-forming fungi in the family Acarosporaceae. Most species in the genus are crustose lichens that grow on rocks in open and arid places all over the world. They may look like a cobblestone road or cracked up old paint, and are commonly called cobblestone lichens or cracked lichens. They usually grow on rock, but some grow on soil (terricolous) or on other lichens. Some species in the genus are fungi that live as parasites on other lichens. Acarospora is a widely distributed genus, with about 128 species according to a 2008 estimate.
Diploschistes is a genus of lichen-forming fungi in the family Graphidaceae. Members of the genus are crustose lichens with a thick, cracked (areolate) body (thallus) with worldwide distribution. The fruiting part (apothecia) are immersed in the thick thallus so as to have the appearance of being small "craters". The widespread genus contains about 43 species.
Buellia is a genus of mostly lichen-forming fungi in the family Caliciaceae. The fungi are usually part of a crustose lichen. In this case, the lichen species is given the same name as the fungus. But members may also grow as parasites on lichens (lichenicolous). The algae in the lichen is always a member of the genus Trebouxia.
Aino Marjatta Henssen, was a German lichenologist and systematist. Her father, Gottfried Henssen, was a folklorist and her mother was Finnish.
Lecanora mugambii is a species of crustose lichen in the family Lecanoraceae. Found in western Kenya, it was described as new to science in 2011.
Lichens are symbiotic organisms made up of multiple species: a fungus, one or more photobionts and sometimes a yeast. They are regularly grouped by their external appearance – a characteristic known as their growth form. This form, which is based on the appearance of vegetative part of the lichen, varies depending on the species and the environmental conditions it faces. Those who study lichens (lichenologists) have described a dozen of these forms: areolate, byssoid, calicioid, cladoniform, crustose, filamentous, foliose, fruticose, gelatinous, leprose, placoidioid and squamulose. Traditionally, crustose (flat), foliose (leafy) and fruticose (shrubby) are considered to be the three main forms. In addition to these more formalised, traditional growth types, there are a handful of informal types named for their resemblance to the lichens of specific genera. These include alectorioid, catapyrenioid, cetrarioid, hypogymnioid, parmelioid and usneoid.
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 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.
John Kenneth Bartlett was a New Zealand plant collector and botanist who specialised in mosses, liverworts, and lichens. In 1974, he found Bartlett's rātā growing south-east of Cape Reinga.
Stereocaulon alpinum is a species of fungus belonging to the family Stereocaulaceae. It is similar to Stereocaulon paschale but differs from it in containing cyanobacteria of the genus Nostoc while S. paschale contains cyanobacteria of the genus Stigonema, which have a darker colour than Nostoc.
Stereocaulon rivulorum is a species of snow lichen belonging to the family Stereocaulaceae.
Stereocaulon groenlandicum is a species of snow lichen belonging to the family Stereocaulaceae.
Xalocoa is a single-species fungal genus in the family Graphidaceae. The genus was circumscribed in 2013 by lichenologists Ekaphan Kraichak, Robert Lücking, and H. Thorsten Lumbsch. It contains Xalocoa ocellata, a corticolous (bark-dwelling), crustose lichen that was originally described by Elias Magnus Fries in 1831.
