''Xylographaceae'' is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

-forming

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

in the order

Baeomycetales 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 ...

. It contains four

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

and 25 species.

Taxonomy

The family was

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

in 1888 by American lichenologist

Edward Tuckerman Edward Tuckerman (December 7, 1817, in Boston, Massachusetts – March 15, 1886) was an American botanist and professor who made significant contributions to the study of lichens and other alpine plants. He was a founding member of the Natural H ...

(as "Xylographei"). His concept of the family included only ''

Agyrium ''Agyrium'' is a genus of saprophytic fungi in the family Agyriaceae. It probably evolved from a lichen ancestor, as it is closely related to many lichenized species of fungi. Taxonomy ''Agyrium'' was first proposed by Elias Magnus Fries in hi ...

'', and the

type genus In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...

, '' Xylographa''. In 1929, British lichenologist Walter Watson published a system of lichen classification and included the genera '' Lithographa'', '' Ptychographa'', and '' Encephalographa'' in the Xylographaceae, leaving out ''Agyrium''. After that, the family was rarely used until it was resurrected in 2015 following

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 of trapelioid fungi in the subclass

Ostropomycetidae The Ostropomycetidae are a subclass of mostly lichen-forming fungi in the class Lecanoromycetes. It contains nine orders and 37 families. Arctomiaceae is the only family in the Ostropomycetidae that associates with cyanobacteria of the order N ...

. In this analysis, it was determined that trapelioid

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

fall into two major

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

groups; the first group – containing the genera '' Rimularia'', '' Placynthiella'', '' Trapeliopsis'', '' Trapelia'', and '' Placopsis'' – are part of the family

Trapeliaceae Trapeliaceae is a family (biology), family of lichens in the order Baeomycetales. The family contains 12 genus, genera and about 125 species. Taxonomy Trapeliaceae was originally circumscription (taxonomy), circumscribed by French lichenologist ...

. The remaining trapelioid genera are in the Xylographaceae.

Description

Most species in the Xylographaceae have linearized, hysteriothecial

ascomata An ascocarp, or ascoma (: ascomata), is the fruiting body (sporocarp (fungi), sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded ascus, asci, each of which typically contains four to ...

. These are ascomata with elongated ascocarps that are initially closed but open by means of a longitudinal fissure that exposes the

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in oth ...

Genera

*'' Lambiella'' – 12 spp. *'' Lithographa'' – 10 spp. *'' Ptychographa'' – 1 sp. *'' Xylographa'' – 2 spp.

References

{{Taxonbar, from=Q28872310 Baeomycetales Lecanoromycetes families Taxa named by Edward Tuckerman Taxa described in 1888 Lichen families