The Arthoniales is the second largest order of mainly crustose lichens, but fruticose lichens are present as well. The order contains around 1500 species, while the largest order with lichenized fungi, the Lecanorales, contains more than 14000 species.
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 Verrucariaceae are a family of mostly lichenised fungi in the order Verrucariales. The lichen-forming species, which comprise the vast majority of the family, have a wide variety of thallus forms, and include crustose (crust-like), foliose (bushy), and squamulose (scaly) representatives. Several characteristics of the spore-bearing structures, the ascomata, define the family, including their perithecioid form–more or less spherical or flask-shaped, with a single opening and otherwise completely enclosed by a wall. Squamulose members of the Verrucariaceae with simple ascospores, and without algae in the spore-bearing region are known as catapyrenioid lichens; there are more than 80 of these species. The family has several dozen lichenicolous (lichen-dwelling) examples, and a few genera that contain solely lichenicolous members. An unusually diverse variety of photobiont partners have been recorded, mostly green algae, but also brown algae and yellow-green algae.
Punctelia is a genus of foliose lichens belonging to the large family Parmeliaceae. The genus, which contains about 50 species, was segregated from genus Parmelia in 1982. Characteristics that define Punctelia include the presence of hook-like to thread-like conidia, simple rhizines, and point-like pseudocyphellae. It is this last feature that is alluded to in the vernacular names speckled shield lichens or speckleback lichens.
Candelariella is a genus of bright yellow, ocher, or greenish yellow crustose or squamulose lichens in the family Candelariaceae. Members of the genus are commonly called eggyolk lichens, goldspeck lichens, or yolk lichens. The genus was circumscribed in 1894 by Swiss lichenologist Johannes Müller Argoviensis, with Candelariella vitellina assigned as the type species.
Subhysteropycnis is a fungal genus in the family Arthoniaceae. This is a monotypic genus, containing the lichenicolous fungus species Subhysteropycnis maculiformans, which is parasitic on Pseudocyphellaria glabra and Pseudocyphellaria homoeophylla.
Pseudocyphellaria is a genus of large, leafy lichens that are sometimes referred to as "specklebelly" lichens. The genus has a widespread distribution, especially in south temperate regions, and contains about 170 species. They resemble Lobaria, except that most species of Pseudocyphellaria have conspicuous pseudocyphellae on their lower surface, a characteristic that was once considered unique to this genus. Some species contain pulvinic acid-related pigments; in these species the soredia and pseudocyphellae can be bright yellow.
Phacopsis is a genus of lichenicolous (lichen-dwelling) fungi. They are parasites of members of the large lichen family Parmeliaceae, of which they are also a member. Originally proposed by Edmond Tulasne in 1852 to contain 3 species, Phacopsis now contains 10 species, although historically, 33 taxa have been described in the genus. Many of the species are poorly known, some of them having been documented only from the type specimen.
Physcia caesia, known colloquially as blue-gray rosette lichen and powder-back lichen, is a species of foliose lichenized fungus. First described by Georg Franz Hoffmann in 1784, it is common across much of Europe, North America and New Zealand, and more patchily distributed in South America, Asia, Australia and Antarctica. There are 2 subspecies: P. c. caesia and P. c. ventosa, as well as a number of distinct forms and varieties. Molecular studies suggest that the species as currently defined may be polyphyletic. It is typically pale gray shading to darker gray in the center, and grows in a small rosette, usually some 2–3 cm (0.79–1.18 in) across at maturity. It only rarely has apothecia, instead reproducing most often vegetatively via soredia, which are piled in round blue-gray mounds across the thallus's upper surface. It grows most often on rock—principally calcareous, but also basaltic and siliceous—and also occurs on bone, bark and soil. It is nitrophilic and is particularly common on substrates where birds perch.
Chaenothecopsis dibbleandersoniarum is a species of fungus in the family Mycocaliciaceae. It was described as new to science in 2003 by Steve Selva, from samples collected on Cape Breton Island, Nova Scotia, Canada. It has also been recorded in Maine. The fungus is lichenicolous, and grows as a parasite on the apothecia and thallus of the lichen Arthonia leucopellaea. It is named after Dr. Alison Dibble and Ms. Frances Anderson, both of whom independently brought the species to the attention of Selva.
Stereocaulon paschale is a species of lichen belonging to the family Stereocaulaceae.
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.
Solenopsora is a genus of lichen-forming fungi in the family Catillariaceae. It has 15 species, with a mostly Northern Hemisphere distribution.
Xenonectriella subimperspicua is a species of lichenicolous fungus in the family Nectriaceae. It has been recorded from South America, Europe, and New Zealand.
Lepraria incana is a species of dust lichen in the family Stereocaulaceae. First described scientifically by Johann Jacob Dillenius in 1741, and then formally by Carl Linnaeus in 1753, it is the type species of the genus Lepraria. The thallus of this species is green to greyish-green, and powdery – as if made of tiny granules. These granules are soredia, which are asexual reproductive structures. Like most members of genus Lepraria, the lichen has few distinguishing features, lacking both a medulla and sexual reproductive structures (apothecia). Chemically, the lichen is characterised by the presence of the secondary chemicals known as divaricatic acid and zeorin.
Graphium samogiticum is a little-known species of lichenicolous (lichen-eating) fungus in the family Microascaceae. It is found in Lithuania, where it parasitises two lichen species that inhabit abandoned gravel pits.
Arthonia stereocaulina is a species of lichenicolous fungus in the family Arthoniaceae.
Mastodia is a genus of lichen-forming fungi in the family Verrucariaceae. It has six species. The genus was circumscribed in 1847 by Joseph Dalton Hooker and William Henry Harvey. The type species, Mastodia tessellata, is a bipolar, coastal lichen. It forms a symbiotic association with the macroscopic genus Prasiola; this is the only known lichen symbiosis involving a foliose green alga. Studies suggest that throughout its geographic range, the lichen comprises two fungal species and three algal lineages that associate.
Cetraria laevigata is a species of ground-dwelling, fruticose (bushy) lichen in the family Parmeliaceae. It was formally described as a new species by Russian lichenologist Kseniya Aleksandrovna Rassadina in 1943. In North America, it is commonly known as the striped Iceland 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.
