| Synarthonia | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Arthoniomycetes |
| Order: | Arthoniales |
| Genus: | Synarthonia Müll.Arg. (1891) |
| Type species | |
| Synarthonia bicolor Müll.Arg. (1891) | |
| Synonyms [1] | |
Synarthonia is a genus of lichen-forming fungi in the order Arthoniales. The genus has not been placed into a family. [2]
Synarthonia was circumscribed by Swiss lichenologist Johannes Müller Argoviensis in 1891, based on collections of the type species, Synarthonia bicolor , from Costa Rica. [3]
Synarthonia is a genus of lichens that typically grows on tree bark (corticolous). These lichens are crustose, meaning they form a thin, crust-like growth that can range in colour from whitish to greenish-grey to green. The fungal body (thallus) may develop either below or on top of the bark's surface, and its texture varies from smooth to warty or powdery. Some species may produce specialised reproductive structures called soredia, while others lack them. The thallus lacks a protective outer layer ( cortex ), and its fungal threads (hyphae) are colourless. [4]
Some species develop distinctive boundaries where they meet other lichens, appearing as black to brown lines. In particular, species like S. psoromica and S. stigmatidialis form fibre-like boundaries, while S. sikkimensis produces root-like structures. The photosynthetic partner ( photobiont ) in these lichens belongs to the Trentepohlia genus of green algae, occurring either as single cells or short chains of round to oval cells. However, some species are non-lichenised and grow parasitically on other lichens, lacking algal cells entirely. [4]
The reproductive structures (ascomata) may appear either singly or in irregular groups. They can be embedded in the thallus or slightly raised above it. The spore-producing surface ( disc ) may be covered with a white, grey, or orange powder-like coating ( pruina ), beneath which it appears brown to orange or translucent light brown to blackish-brown, sometimes with remnants of the thallus tissue. [4]
The internal structure is complex, with various layers serving different functions. The spores are produced in sac-like structures (asci) that typically contain eight spores each. The spores themselves start colourless but may develop brown ornamentation at maturity. They can be divided by cross-walls or appear more complex with multiple compartments ( muriform ). Additional asexual reproductive structures called pycnidia appear as black dots and produce small, colourless, rod-shaped spores (conidia). [4]
The genus is characterised by the presence of various secondary metabolites, including parietin, evernic acid, psoromic acid, and various xanthones, though some species lack secondary compounds entirely. Most species do not contain calcium oxalate crystals, with S. muriformis being a notable exception, occasionally accumulating these crystals in its reproductive structures. [4]
Species of Synarthonia typically have restricted geographical distributions. Most species are known only from single locations or regions: S. bicolor has been documented solely in Costa Rica, while S. psoromica and S. sikkimensis are known only from India. S. sarcographoides has been reported just once from northeastern Brazil, and S. stigmatidialis has a single recorded occurrence in Mexico. [4]
The lichen-forming members of the genus primarily inhabit tropical regions, with fewer species extending into temperate areas. These lichens show a strong preference for growing on tree bark, particularly favouring smooth-barked trees in exposed conditions such as branches and solitary trees. Some species within the genus have evolved a parasitic lifestyle: members of the S. ochracea complex specifically target species of Graphis lichens during their early development stages, while S. rimeliicola exclusively grows on lichens belonging to the family Parmeliaceae. [4]
The current understanding of Synarthonia's distribution may be incomplete, as these lichens are often inconspicuous and easily overlooked in the field. Additionally, many specimens in herbarium collections may be misidentified and filed under different names, particularly as species of the related genus Arthonia . [4]
As of January 2025 [update] , Species Fungorum (in the Catalogue of Life) accepts 24 species of Synarthonia: [5]
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 mostly lichen-forming fungi in the order Arthoniales, established by the French botanist François Fulgis Chevallier in 1826. Species in the family exhibit various growth forms, including crustose and fruticose (shrub-like) thalli, and diverse reproductive structures. Roccellaceae species typically have disc-like or slit-like fruiting bodies, often with distinct blackened margins. Molecular phylogenetics studies have revealed considerable genetic diversity and complex evolutionary histories within the family.
Stirtonia is a genus of lichen-forming fungi in the family Arthoniaceae. It contains 22 species of corticolous (bark-dwelling) crustose lichens found primarily in tropical regions. The genus was circumscribed by the British lichenologist Annie Lorrain Smith in 1926, with Stirtonia obvallata assigned as the type species. The species epithet honours the Scottish lichenologist James Stirton.
Arthothelium is a genus of lichen-forming fungi in the family Arthoniaceae.
Arthonia is a genus of lichens in the family Arthoniaceae. It was circumscribed by Swedish botanist Erik Acharius in 1806.
Tylophoron is a genus of lichen-forming fungi in the family Arthoniaceae. It comprises seven species of crustose lichens, most of which occur in tropical regions.
Briancoppinsia is a fungal genus in the family Arthoniaceae. It is monotypic, containing the single species Briancoppinsia cytospora, a lichenicolous fungus that parasitises parmelioid lichens, as well as Cladonia, Lepra, and Lecanora conizaeoides, among others. The species was first described scientifically by Léon Vouaux in 1914 as Phyllosticta cytospora.
Schizotrema is a genus of lichen-forming fungi in the family Graphidaceae. The genus was circumscribed in 2009 by Armin Mangold and H. Thorsten Lumbsch.
Synarthonia leproidica is a species of saxicolous (rock-dwelling) and crustose lichen in the order Arthoniales. Found in Luxembourg, it was formally described as a new species in 2020 by lichenologists Damien Ertz, André Aptroot, and Paul Diederich. The type specimen was collected in the Vallée du Lellgerbaach (Lellingen) at an elevation of 323 m (1,060 ft). Here the lichen was found on a siliceous wall at the edge of a forest path in an oak-hornbeam forest. It has a pale greyish crust-like thallus with dark brown/violet tinges. It has a leproid growth form, meaning that it looks like it is made of granules; the specific epithet refers to this characteristic. The thallus forms patches that are about 0.5–5 mm in diameter, although neighbouring patches can coalesce to form larger patches up to 10 cm (4 in) in diameter. Synarthonia leproidica contains psoromic acid, a secondary chemical that can be detected with thin-layer chromatography.
Inoderma is a genus of lichen-forming fungi in the family Arthoniaceae. It was resurrected for use in 2015 for a small group of species with the following features: elevated, white pruinose pycnidia, immersed to adnate white pruinose apothecia, and a weakly gelatinized hymenium. Inoderma byssaceum was assigned as the type species for the genus.
Bryostigma is a genus of fungi of uncertain familial placement in the order Arthoniales. The genus is characterised by its thin, patchy growth that either partially embeds into its growing surface or forms an irregular, granular surface, with distinctive red or blue iodine staining of its hyphae and very small fruiting bodies. Most Bryostigma species are parasitic (lichenicolous), growing on other lichens, though a few species like B. lapidicola grow independently on stone or moss. While the genus was initially established with a single species growing on moss, it was significantly expanded in 2020 when several species were transferred from the related genus Arthonia based on DNA analysis, though this taxonomic reclassification has been subject to some scientific dispute. As of 2024, the genus includes seventeen species – thirteen parasitic and four independent lichen species.
Reichlingia is a genus of lichen-forming fungi in the family Arthoniaceae. It has seven species. The genus was originally circumscribed by Paul Diederich and Christoph Scheidegger in 1996, with Reichlingia leopoldii as the type, and at that time, only species. The fungus was at first thought to be a lichenicolous (lichen-dwelling) fungus, but is now considered a lichenised hyphomycete.
Piccolia is a small genus of crustose lichens in the class Lecanoromycetes. First circumscribed by Italian lichenologist Abramo Bartolommeo Massalongo in 1864, it contains ten species. Due to a lack of molecular data, it has not been assigned to an order or family.
Gintarasia is a genus of lichen-forming fungi in the family Graphidaceae. It has seven species, all of which are found in Australia. Gintarasia species are corticolous (bark-dwelling), crustose lichens with a thelotremoid form.
Sporodophoron is a genus of lichen-forming fungi in the family Arthoniaceae. It includes four corticolous (bark-dwelling) crustose lichen species. Sporodophoron is uniquely characterised by the formation of fruiting structures called sporodochia, which are open conidiomata in the form of tufts of conidiophores on the thallus. Although these lichens bear a strong resemblance to Inoderma, another genus within the same family, Sporodophoron's distinct chemical makeup sets it apart from its lichen relatives. Collectively, the genus has a widespread geographical distribution in the Northern Hemisphere, with species found in distinct habitats in North America, Europe, Japan, and the Russian Far East.
Coniocarpon is a genus of lichen-forming fungi in the family Arthoniaceae. It has eight species of corticolous (bark-dwelling) lichens. This genus is distinct for its crystalline orange, red, and purple quinoid pigments in the ascomata that turn purple in potassium hydroxide solution, its colourless, transversely septate ascospores with large apical cells, and its rounded to lirellate ascomata.
Microtheliopsis is a genus of lichen-forming fungi in the family Microtheliopsidaceae. It comprises four species of foliicolous (leaf-dwelling) crustose lichens.
Arthonia radiata, the asterisk lichen, is a common and widepspread species of corticolous (bark-dwelling), crustose lichen in the family Arthoniaceae.
Diarthonis is a fungal genus in the family Graphidaceae. Originally created in 1909 but long unused, the genus was revived in 2020 to accommodate D. spadicea when molecular studies showed this species fell outside the main Arthonia clade. The species grows as a thin, greyish to greenish crust beneath tree bark, producing small black disc-like reproductive structures (apothecia) that resemble drops of tar. It is considered an indicator of ecological continuity in old-growth broadleaved forests, particularly those dominated by English oak, and is listed as near-threatened in some regions.
Pachnolepia is a small fungal genus in the family Arthoniaceae. It comprises two species of corticolous (bark-dwelling) lichens.