A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. The combined lichen has properties different from those of its component organisms. Lichens come in many colors, sizes, and forms. The properties are sometimes plant-like, but lichens are not plants. Lichens may have tiny, leafless branches (fruticose), flat leaf-like structures (foliose), flakes that lie on the surface like peeling paint (crustose), a powder-like appearance (leprose), or other growth forms.
The Cladoniaceae are a family of lichenized fungi in the order Lecanorales. The reindeer moss and cup lichens (Cladonia) belong to this family. The latter genus, which comprises about 400 species, forms a major part of the diet of large mammals in taiga and tundra ecosystems.
Chaenotheca is a genus of lichenized fungi within the family Coniocybaceae. The sexual reproduction structures are a mass of loose ascospores that are enclosed by a cup shaped exciple sitting on top of a tiny stalk, having the appearance of a dressmaker's pin, hence the common name pin lichen. Genus members are also commonly called needle lichens.
Agyrium is a genus of saprophytic fungi in the family Agyriaceae. It probably evolved from a lichen ancestor, as it is closely related to many lichenized species of fungi.
The Clavulinaceae are a family of fungi in the order Cantharellales. The family is not well defined, but currently comprises species of clavarioid fungi as well as some corticioid fungi. These species are nutritionally diverse, some being ectomycorrhizal, others wood-rotting saprotrophs, others lichenized, and yet others lichenicolous.
Flavoparmelia caperata, the common greenshield lichen, is a medium to large foliose lichen that has a very distinctive pale yellow green upper cortex when dry. The rounded lobes, measuring 3–8 mm (0.1–0.3 in) wide, usually have patches of granular soredia arising from pustules. The lobes of the thallus may be smooth, but quite often have a wrinkled appearance especially in older specimens. The lower surface is black except for a brown margin; rhizoids attached to the lower surface are black and unbranched.
Protopannaria is a genus of lichenized fungi in the family Pannariaceae. The genus was circumscribed in 2000.
Erioderma is a genus of lichenized fungi in the family Pannariaceae. They are commonly called mouse ears or felt lichens, and are small, pale brown to olive-brown foliose cyanolichens with a fuzzy upper surface that have the cyanobacteria Scytonema as their photobiont. Most species are found in the tropics of Central and South America, although three species are found in coastal regions of North America where they generally grow on mossy branches in humid sites. All North American species are rare, and two of them, Erioderma mollissimum and Erioderma pedicellatum, are listed as endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Erioderma pedicellatum is also listed as critically endangered on the IUCN Red List of Threatened Species. Species of Erioderma can resemble Pannaria, Leioderma, or small Peltigera, but their fuzzy upper surface and lack of veins on their lower surface distinguishes them from these lichens.
Xanthoria is a genus of lichenized fungi in the family Teloschistaceae. Common names include orange lichen, orange wall lichen, and sunburst lichen. They can be identified by their characteristic Squamulose morphology with distinctive "fairy cups".
Cryptothecia is a genus of white to greenish crustose lichens that grow on bark, wood, or leaves. in tropical or subtropical areas worldwide. It has a conspicuous prothallus that develops around its periphery which can be bright red in some species, hence the common name wreath lichen. The main vegetative body (thallus) lacks a cortex.
Melanomma is a genus of fungi in the family Melanommataceae. It probably evolved from a lichen ancestor, as it is closely related to many lichenized species of fungi.
Rhizoplaca is a genus of lichenized fungi in the Lecanoraceae family. Members of the genus are commonly called rimmed navel lichens because of their umbillicate growth form and lecanorine apothecia, also rock-posy lichen and rockbright. The genus has a widespread distribution and contains 11 species.
Ameliella is a genus of lichenized fungi in the Lecanoraceae family. Described in 2008, the genus contains two species, A. andreaeicola and A. grisea, that were collected from high elevations in the Scottish Highlands. The two species have also been found in single instances in British Columbia and Northern Norway. The generic name is derived from the Greek ameleo, meaning "neglected" or "overlooked"; it was originally intended to be Amelia, which is also the first name of the daughter of one of the authors, but this name had previously been used for another genus and was therefore ineligible for use according to the rules of mycological nomenclature. Ameliella appears to have some similarity with the lichen genus Miriquidica.
Cryptothele is a genus of lichen within the Lichinaceae family. The genus contains eight species, two of which are found in North America.
The Arthrorhaphidaceae are a family of lichenized fungi in the division Ascomycota. This is a monotypic taxon, containing the single genus Arthrorhaphis, first described by Theodor Magnus Fries in 1860. The family was named by J. Poelt and J. Hafellner in 1976. Species in this family have a widespread distribution in temperate and montane habitats. They grow symbiotically with green algae, or parasitically on other lichens.
Athelia is a genus of corticioid fungi in the family Atheliaceae. Some species are facultative parasites of plants and of lichens. The widespread genus contains 28 species. However, Athelia rolfsii was found to belong in the Amylocorticiales in a molecular phylogenetics study, but has yet not been renamed.
Nesolechia is a genus of fungi that grows on lichens. It probably evolved from a lichen ancestor, as it is closely related to many lichenized species of fungi.
Chrysothrix is a lichenized genus of fungi in the family Chrysothricaceae. They are commonly called gold dust lichens or sulfur dust lichens, because they are bright yellow to greenish-yellow, sometimes flecked with orange, and composed entirely of powdery soredia. Apothecia are never present in North American specimens.
