The Arthoniaceae are a family of lichenized, lichenicolous and saprobic fungi in the order Arthoniales. The Arthoniaceae is the largest family of Arthoniales, with around 800 species. Most species in Arthoniaceae belong in Arthonia which is the largest genus with 500 species. The second and third largest genus is Arthothelium with 80 species, and Cryptothecia with 60 species.
The Roccellaceae are a family of fungi in the order Arthoniales, circumscribed by French botanist François Fulgis Chevallier in 1826. This family is distinguished by a wide variety of growth forms, including crustose and fruticose thalli, and a diverse range of reproductive structures. Roccellaceae species typically have apotheciate or lirellate ascomata, often with distinct carbonised (blackened) margins. The family has been extensively studied through molecular phylogenetics, revealing significant genetic diversity and complex evolutionary histories.
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 (ecorticate and is often immersed in the substrate or byssoid. The medulla is white, well defined, and often peppered with calcium oxalate crystals. Ascomata are not well defined, being cushions of soft white mycelium immersed in the medullary tissue, hence the name from the Greek krypto = "to conceal" and theke = "a container or sheath". It contains Trentepohlia, a green alga, as its photobiont partner.
Chiodecton is a genus of lichens in the family Roccellaceae. The genus was circumscribed by the lichenologist Erik Acharius in 1814, with Chiodecton sphaerale assigned as the type species.
Sagenidiopsis isidiata is a species of corticolous (bark-dwelling) byssoid lichen in the family Arthoniaceae. Found in tropical montane rainforests throughout Central America, South America, and the Antilles, it was described as new to science in 2011. The lichen is characterised by its cream-coloured to greyish thallus and numerous pseudoisidia, which are small, cylindrical outgrowths on its surface.
Herpothallon is a genus of crustose lichens in the family Arthoniaceae. It has about 50 species.
Enterographa lichexanthonica is a species of crustose and corticolous (bark-dwelling) lichen in the family Roccellaceae. Found in the Brazilian Amazon, it was formally introduced as a new species in 2017 by lichenologists Marcela Eugenia Cáceres and André Aptroot. The type specimen was collected by the authors from the Adolfo Ducke Forest Reserve, along trails near a field station; here, it was found growing on tree bark in a old-growth rainforest. The lichen has a thin, dull, pale greenish thallus surrounded by a thin black prothallus. Its ascospores are hyaline, have seven septa, and measure 21–27 by 5–6 μm; they have a 1 μm-thick gelatinous sheath surrounding them. The specific epithet lichexanthonica refers to lichexanthone, a secondary chemical that occurs in the cortex of the lichen. This compound causes the lichen to fluoresce yellow when a UV light is shone upon it. Enterographa lichexanthonica is morphologically similar to E. kalbii, but this latter species has lichexanthone only on the ascomata, not on the thallus.
Vigneronia is a genus of lichen-forming fungi in the family Roccellaceae. It has five species. The genus was circumscribed in 2014 by Damien Ernst, with Vigneronia spieri assigned as the type species. This species, originally described as Schismatomma spieri from collections made in the Galápagos Islands, has since been recorded from mainland Ecuador and the Antilles (Curaçao). The genus is named after Ernst's wife, Nathalie Vigneron, who accompanied him on collecting trips.
Gyrographa is a genus of lichen-forming fungi in the family Roccellaceae. The genus was circumscribed in 2014 by Damien Ernst and Anders Tehler, with Gyrographa gyrocarpa assigned as the type species. This lichen, originally described by Julius von Flotow in 1825, was first placed in the genus Opegrapha. Species in the genus have a crustose thallus lacking a cortex, and a dark brown prothallus. The photobiont partner is trentepholioid. The hypothecium is thick and carbonised, and the ascospores lack a gelatinous sheath; these characteristics distinguish it from Opegrapha species. The genus name alludes to the gyrose ascomata of the type species.
Ocellomma is a genus of lichen-forming fungi in the family Roccellaceae. The genus was circumscribed in 2014 by Damien Ertz and Anders Tehler, following a molecular phylogenetic-based revision of the Roccellaceae. The type species, O. picconianum, was originally named Lecania picconiana by Francesco Baglietto in 1862, described from specimens collected in Italy. DNA-based phylogenetic analysis showed that it occupied a distinct genetic lineage, deserving of recognition as a new genus. The genus name Ocellomma alludes to the whitish rims on the small ascomata that contrast with the discs, giving them the appearance of small eyes.
Gossypiothallon is a fungal genus of uncertain familial placement in the order Arthoniales. It contains the single species Gossypiothallon appendisporum, a corticolous (bark-dwelling), crustose lichen found in South Solomons. Both the genus and species were described as new to science in 2014 by Dutch lichenologist André Aptroot. The type specimen was collected from Kolombangara island at an altitude of 700 m (2,300 ft), where it was found growing on bark.
Vigneronia spieri is a species of corticolous (bark-dwelling), crustose lichen in the family Roccellaceae. It is found in the Galápagos Islands, mainland Ecuador and the Antilles (Curaçao).
Enterographa incognita is a little-known species of crustose lichen in the family Roccellaceae. Found in Southeast Thailand, it is characterised by its sorediate features and its distinct ascomata and ascospores. This lichen, only known to occur in its type locality, thrives on large trunks in a mangrove environment.
Enterographa rotundata is a species of corticolous (bark-dwelling) crustose lichen in the family Roccellaceae. This species was discovered in Brazil, growing on the smooth bark of trees in the Brazilian Caatinga forest. It has round apothecia, a feature that sets it apart from most of its kind.
Fulvophyton is a genus of lichen-forming fungi in the family Roccellographaceae. It has 11 species. Fulvophyton is characterised by its crust-like thallus, which is often pale yellowish-brown in colour. This genus features a photobiont from the green algal genus Trentepohlia and exhibits a unique arrangement of reproductive structures.
Neosergipea bicolor is a rare species of corticolous (bark-dwelling), crustose lichen in the family Arthoniaceae. Found only in Brazil and described as a new species in 2017, Neosergipea bicolor is characterised its dual-coloured appearance.
Neosergipea hyphosa is a species of corticolous (bark-dwelling) lichen in the family Roccellaceae. This lichen species is uniquely characterised by its olive-green thallus—a type of vegetative tissue—and spherical ascomata, or fungal reproductive structures. It is most commonly found on tree bark in Brazil. The name hyphosa alludes to the distinct hyphose surface of the thallus.
Neosergipea septoconidiata is a species of corticolous (bark-dwelling) lichen in the family Roccellaceae. It is a unique species of lichen that grows on the bark of trees in the primary forests of Brazil with its bluish-grey thallus and bright orange pycnidia that have a fluffy hyphal surface.
Cryptophaea is a genus of lichen-forming fungi in the family Arthoniaceae. Initially described as a monotypic genus in 2016 with the type species, C. phaeospora, from the Congo Basin, it was expanded in 2024 to include four species of crustose lichens found in Brazil. Cryptophaea species are characterised by their firmly attached thalli, which are typically whitish grey-green and hydrophobic. The genus has diverse morphological features, including pseudoisidia and soredia in some species. Cryptophaea lichens are corticolous, growing on tree bark in various tropical forest ecosystems, from near sea level to elevations over 1000 metres. Recent molecular phylogenetic studies have revealed complex relationships between Cryptophaea and other genera within Arthoniaceae, suggesting potential taxonomic revisions may be necessary as more data becomes available.
Synarthothelium is a genus of lichen-forming fungi of uncertain familial placement in the order Arthoniales. It has two species of corticolous (bark-dwelling) crustose lichens that occur in tropical regions of the Americas.
