Abstract
Hysteriaceous ascomycetes are an interesting and important group of fungi belonging to a small number of families and orders in the class Dothideomycetes. They can be saprobes, endophytes and/or ectomycorrhizal. Hysteriaceous fungi mainly occur on twigs or bark of various woody and herbaceous plants in terrestrial and aquatic environments worldwide. They have evolved convergently at least five times, and further studies are needed to resolve the taxonomic placement of new and previously described taxa. In this study, we introduce a new order, Gloniales, to accommodate Glonium, a new family, Acrogenosporaceae, to accommodate Acrogenospora, five new species (Hysterium doimaeensis, H. thailandica, Hysterobrevium hakeae, Hy. rosae and Mytilinidion didymospora) and a new combination (Purpurepithecium minus). New records are provided with descriptions and illustrations are given for Gloniopsis subrugosa, Hysterium angustatum and Hysterographium fraxi. The findings are supported by morphological and phylogenetic analyses of LSU SSU, RPB2 and TEF1 sequence data. In addition, amino acid sequences of RPB2 were phylogenetically analyzed.