Pezizomycotina make up most of the Ascomycota fungi and include most lichenized fungi too. Pezizomycotina contains the filamentous ascomycetes and is a subdivision of the Ascomycota. It is more or less synonymous with the older taxon Euascomycota. These fungi reproduce by fission rather than budding and this subdivision includes almost all the ascus fungi that have fruiting bodies visible to the naked eye.
Eurotiomycetes is a large class of ascomycetes with cleistothecial ascocarps within the subphylum Pezizomycotina, currently containing around 3810 species according to the Catalogue of Life. It is the third largest lichenized class, with more than 1200 lichen species that are mostly bitunicate in the formation of asci. It contains most of the fungi previously known morphologically as "Plectomycetes".
The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2700 species in 71 genera, it is the largest family of lichen-forming fungi. The most speciose genera in the family are the well-known groups: Xanthoparmelia, Usnea, Parmotrema, and Hypotrachyna.
The order Sordariales is one of the most diverse taxonomic groups within the Sordariomycetes.
Gyalectales is an order of lichen-forming fungi in the class Lecanoromycetes. It contains 5 families, 15 genera and about 550 species.
Arthoniomycetes are a class of ascomycete fungi. It includes two orders: Arthoniales and Lichenostigmatales. Most of the taxa in these orders are tropical and subtropical lichens.
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.
Geoglossaceae is a family of fungi in the order Geoglossales, class Geoglossomycetes. These fungi are broadly known as earth tongues. The ascocarps of most species in the family Geoglossaceae are terrestrial and are generally small, dark in color, and club-shaped with a height of 2–8 cm. The ascospores are typically light-brown to dark-brown and are often multiseptate. Other species of fungi have been known to parasitize ascocarps. The use of a compound microscope is needed for accurate identification.
Peltigerales is an order of lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. The taxonomy of the group has seen numerous changes; it was formerly often treated as a suborder of the order Lecanorales. It contains two suborders, eight families and about 45 genera such as Lobaria and Peltigera.
The Acarosporales are an order of fungi in the class Lecanoromycetes. Phylogenetic analyses conducted using the sequences of both the protein-coding gene RPB2 as well as nuclear ribosomal genes place this order within the subclass Acarosporomycetidae.
The Acarosporaceae are a family of fungi in the order Acarosporales. Members of this family have a widespread distribution, and are mostly lichenized with green algae. According to a 2021 estimate, the family contains 11 genera and about 260 species. The family is characterised by a hamathecium formed of paraphysoids.
The Ostropomycetidae are a subclass of mostly lichen-forming fungi in the class Lecanoromycetes. The subclass was circumscribed in 2004 by Catherine Reeb, François M. Lutzoni, and Claude Roux. It contains ten orders and 36 families.
The Baeomycetales are an order of mostly lichen-forming fungi in the subclass Ostropomycetidae, in the class Lecanoromycetes. It contains 8 families, 33 genera and about 170 species. As a result of molecular phylogenetics research published in the late 2010s, several orders were folded into the Baeomycetales, resulting in a substantial increase in the number of taxa.
The Mycocaliciaceae are a family of seven genera and about 90 species of fungi in the order Mycocaliciales.
The Arctomiaceae are a family of lichenized fungi in the Ascomycota, class Baeomycetales. The family was named by Theodor Magnus Fries in 1861, with Arctomia as the type genus. Species in this family are found in arctic and subarctic habitats, usually associated with bryophytes.
The Caliciaceae are a family of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. Although the family has had its classification changed several times throughout its taxonomic history, the use of modern molecular phylogenetic methods have helped to establish its current placement in the order Caliciales. Caliciaceae contains 36 genera and about 600 species. The largest genus is Buellia, with around 300 species; there are more than a dozen genera that contain only a single species.
Trapeliaceae is a family of lichens in the order Baeomycetales. The family contains 12 genera and about 125 species.
Leprocaulaceae is a family of mostly lichen-forming fungi. It is the single family in the monotypic order Leprocaulales. Leprocaulaceae contains three genera and about 33 species.
Xylographaceae is a family of lichen-forming fungi in the order Baeomycetales. It contains four genera and 25 species.
Rhizocarpales are an order of lichen-forming fungi in the subclass Lecanoromycetidae of the class Lecanoromycetes. It has two families, Rhizocarpaceae and Sporastatiaceae, which contain mostly crustose lichens.
