Numerous species of microscopic fungi inhabit mosses and hepatics. They are severely overlooked and their identity and nutritional strategies are mostly unknown. Most of these bryosymbiotic fungi belong to the Ascomycota. Their fruit-bodies are extremely small, often reduced and simply structured, which is why they cannot be reliably identified and classified by their morphological and anatomical characters. A phylogenetic hypothesis of bryosymbiotic ascomycetes is presented. New sequences of 78 samples, including 61 bryosymbionts, were produced, the total amount of terminals being 206. Of these, 202 are Ascomycetes. Sequences from the following five gene loci were used: rDNA SSU, rDNA LSU, RPB2, mitochondrial rDNA SSU, and rDNA 5.8S. The program TNT was used for tree search and support value estimation. We show that bryosymbiotic fungi occur in numerous lineages, one of which represents a newly discovered lineage among the Ascomycota and exhibits a tripartite association with cyanobacteria and sphagna. A new genus Trizodia is proposed for this basal clade. Our results demonstrate that even highly specialized life strategies can be adopted multiple times during evolution, and that in many cases bryosymbionts appear to have evolved from saprobic ancestors.

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The monotypic genus Fuscoscypha possesses hairs similar as in the genus Hyaloscypha but differs by grey-olivaceous-brown apothecia with short dark stipes. Molecular data proves that the pigmentation does not permit delimitation of a separate genus, as white and brown taxa do not form separate clades. Followingly, Fuscoscypha is here considered to be a synonym of Hyaloscypha. Three of the here treated four species have an olivaceous-brown excipulum. Two are saprophytes on decaying leaves and fruits of angiosperms: F. acicularum, the type species of Fuscoscypha, and Hyaloscypha fuscostipitata comb. nov. (formerly placed in Betulina). Two are biotrophic parasites on Bryophyta: Hyaloscypha hepaticola comb. nov. (formerly placed in Trichopeziza) and the hyaline-excipled Hyaloscypha albocarpa spec. nov. which is otherwise very similar to H. hepaticola. The type species of the genus Betulina, B. hirta, is found to be an earlier synonym of Urceolella salicicola (= U. graddonii). The new combination Urceolella hirta is therefore proposed, hence Betulina is considered a synonym of Urceolella.