''Pyrenidium'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of lichenicolous (

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

. It is the only genus in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Pyrenidiaceae. It has 13 species.

Taxonomy

The genus was

circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every polyg ...

by Finnish lichenologist William Nylander in 1865, with ''

Pyrenidium actinellum ''Pyrenidium'' is a genus of lichenicolous (lichen-dwelling) fungi. It is the only genus in the family Pyrenidiaceae. It has 13 species. Taxonomy The genus was circumscribed by Finnish lichenologist William Nylander in 1865, with '' Pyrenidium a ...

'' assigned as the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

. The family was originally proposed by

Alexander Zahlbruckner Alexander Zahlbruckner (31 May 1860, Svätý Jur – 1938, Vienna) was an Austrian- Hungarian botanist who specialized in the study of lichens. Johann Babtist Zahlbruckner, an earlier Austrian botanist, was his grandfather. From 1878 to 1883 ...

in 1898, and later resurrected for use in 2019. ''Pyrenidium'' was previously classified in Dacampiaceae, but

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

analysis showed that this family was polyphyletic, and that ''Pyrenidium'' originated from a

lineage Lineage may refer to: Science * Lineage (anthropology), a group that can demonstrate its common descent from an apical ancestor or a direct line of descent from an ancestor * Lineage (evolution), a temporal sequence of individuals, populati ...

distinct from the genera in that family.

Description

Members of the genus have ascomata that are perithecioid in form, often with blue-green

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

in the upper wall of the peridia. Their ascomata are either immersed in the

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman * Michel Host ...

thallus, or bursting through surface (''erumpent''), exposing the upper part of the structure (sometimes still covered by tissue of the host

thalli Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were ...

). They have bitunicate

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

that contain from 4 to 8

ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

s. Infection by the fungus sometimes causes

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...

-like malformations of the host thallus.

Species

, Species Fungorum (in the

Catalogue of Life The Catalogue of Life is an online database that provides an index of known species of animals, plants, fungi, and microorganisms. It was created in 2001 as a partnership between the global Species 2000 and the American Integrated Taxonomic Info ...

) accepts 13 species of ''Pyrenidium'': * ''

'' * '' Pyrenidium aggregatum'' * '' Pyrenidium borbonicum'' * '' Pyrenidium coccineum'' * '' Pyrenidium cryptotheciae'' * '' Pyrenidium hetairizans'' * '' Pyrenidium hypotrachynae'' * '' Pyrenidium macrosporum'' * '' Pyrenidium octosporum'' * '' Pyrenidium santessonii'' * '' Pyrenidium sporopodiorum'' * '' Pyrenidium ucrainicum'' * '' Pyrenidium zamiae''

References

{{Taxonbar, from=Q10647248 Pleosporales Taxa described in 1865 Dothideomycetes genera Lichenicolous fungi Taxa named by William Nylander (botanist)