Agonimia flabelliformis sp. nov. (Verrucariaceae, Ascomycota) is described as a new species from the Czech Republic, Germany and Great Britain. Except for the distinctive, flabelliform to minutely coralloid thallus the species mostly resembles A. allobata. It differs from other related species of Agonimia in the absence of cortical papillae and in ascospore size. The distinctness of the new species and its placement within the genus Agonimia is supported by analyses of mitochondrial small subunit ribosomal DNA sequences from several samples of the taxon, and from many other representatives of Verrucariales including newly sequenced A. repleta and A. vouauxii. Additionally, ITS rDNA sequence data supports the distinction of A. flabelliformis from A. allobata. However, A. allobata was found to be highly variable and relationships, as well as the monophyly of taxa within Agonimia, are still unresolved and need further investigation.

The phylogeny of the Micarea prasina group was investigated using mitochondrial small subunit ribosomal DNA sequences from 14 taxa representing this group, four other members of the genus Micarea, and Psilolechia lucida as an outgroup. A total of 31 new mtSSU rDNA sequences were generated, including 10 from the M. micrococca complex. Bayesian, maximum parsimony (MP) and maximum likelihood (ML) methods were used to analyse the data. The results show that M. micrococca is not monophyletic and forms three strongly supported lineages: 1) M. micrococca s. str., 2) M. byssacea (Th. Fr.) Czarnota, Guzow-Krzemińska & Coppins comb. nov., and 3) a putative taxon that requires further studies. Micarea viridileprosa is a sister species to M. micrococca s. str. and the recently described M. nowakii is a sister species to M. prasina s. str. The placement of M. tomentosa within the M. prasina group is confirmed. Micarea hedlundii appears to be more closely related to the M. micrococca complex than M. prasina s. str. Descriptions, illustrations, taxonomic remarks, distribution and habitat data for M. micrococca s. str. and M. byssacea are provided. A lectotype for Biatora byssacea Hampe non Zwackh and a neotype for Catillaria prasina β [var.] byssacea are selected.

The new genus Aptrootia Lücking & Sipman is described for Thelenella terricola, an enigmatic terricolous and muscicolous, pyrenocarpous taxon known from Papua New Guinea and Costa Rica, and the new combination Aptrootia terricola (Aptroot) Lücking, Umaña & Chaves comb. nov. is introduced. Aptrootia is characterized by completely immersed perithecia with brown-black ostiolar region, surrounded by a white, cartilaginous thallus resembling that of Gomphillaceae. The hamathecium is typical of Trypetheliaceae, with thin, anastomosing paraphysoids embedded in a gelatinous matrix, but the dark brown ascospores are otherwise unknown within the family. The only known species was tentatively described in Thelenella, but hamathecium type and molecular data place Aptrootia within Trypetheliaceae.