Arctomiaceae

The Arctomiaceae are a family of lichen-forming 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. In overall morphology, the Arctomiaceae combine features that are otherwise uncommon together within the Ostropomycetidae: a consistent association with cyanobacterial genus Nostoc, gelatinous thalli, and fruiting bodies that develop openly rather than being enclosed.

==Classification== The order Arctomiales was proposed by Soili Stenroos, Jolanta Miadlikowska, and François Lutzoni in 2014 to contain this family. In 2018, the class Lecanoromycetes was revised using a temporal approach that uses time-calibrated chronograms to define temporal bands for comparable ranks for orders and families. In this work, the orders Arctomiales, Hymeneliales, and Trapeliales were synonymized with Baeomycetales. In a subsequent review of the use of this method for biological classification of lichens, Robert Lücking considered this merge justified. This synonymy was also accepted in later compilations of fungal classification, and Arctomiaceae is classified in the order Baeomycetales.