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Bryoria (Parmeliaceae, Ascomycota) is one of the dominant genera of hair lichens in western North America and is characteristic of high-elevation conifer forest ecosystems. In areas where Bryoria is abundant, it is common to find thalli in which the thalline filaments become conglutinated, forming brittle dead zones. After sampling Bryoria thalli across western Canada and the northwestern United States at different times of the year, we found that this dieback phenomenon is associated with the winter growth of a mold-forming basidiomycete. We report that this fungus belongs to Athelia (Atheliaceae, Basidiomycota), a genus known to contain lichen pathogens, most notably A. arachnoidea . By sequencing a combination of genetic markers-nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), partial nuc 28S rDNA (28S), and partial translation elongation factor 1-α ( TEF1 )-paired with morphometric analyses, we reveal the involvement of at least three additional lineages of lichen-associated Athelia and describe one as a new species, A. abscondita. Athelia abscondita is morphologically distinguished from other Athelia species by its basidia and basidiospores, was found to frequently infect members of Bryoria sect. Implexae , and was occasionally on other foliose and fruticose species within Parmeliaceae.

Contributing to the process of reassigning lecideoid lichens to natural taxa, we assessed phylogenetic relationships and species delimitation in the Calvitimela aglaea complex (Tephromelataceae) using DNA sequence data and morphological/anatomical and chemical characters. Phylogenetic analysis of nuclear (ITS, MCM7, TEF1-α) and mitochondrial (ribosomal SSU) DNA sequences revealed Mycoblastus as sister to a strongly supported clade comprising Calvitimela, Tephrolema and Violella. Species of these three genera fall into six strongly supported subclades with low backbone resolution. Two of these are represented by Tephromela and Violella, which are readily circumscribed morphologically. The remaining four subclades encompass lineages that have until now been assigned to Calvitimela. While Tephromela and Violella as currently circumscribed are recovered as monophyletic in our analyses, Calvitimela is paraphyletic, with four deeply divergent clades. We recognize these four clades as subgenera Calomela, Calvitimela, Paramela and Severidea. Our molecular results further support the recognition of two recently discovered sterile crusts as new species, Calvitimela cuprea and C. livida, distinguished from previously known species by their production of asexual diaspores and from each other by secondary metabolite chemistry. We also report Calvitimela perlata as new for continental North America., (© 2015 by The Mycological Society of America.)