Abstract
The taxonomy of the corticioid fungi from the class Atractiellomycetes (Pucciniomycotina, Basidiomycetes) currently addressed to the genus Helicogloea, is revised based on morphological and nuclear ribosomal DNA (ITS and LSU) data. The genus is restricted to 25 species with semitranslucent, gelatinous basidiocarps lacking differentiated cystidia and clamps on hyphae, of which 11 are described as new to science. The asexual genus Leucogloea is placed as a synonym of Helicogloea s. str. Since the type species of Saccoblastia, S. ovispora, is combined to Helicogloea, a new genus, Saccosoma, is introduced to encompass Saccoblastia farinacea and six related species, one of which is described as new. In contrast to Helicogloea in the strict sense, the basidiocarps of Saccosoma are arid, not gelatinized, and hyphae are clamped. The third lineage of the corticioid Atractiellomycetes is represented by the Bourdotigloea vestita complex. Species of Bourdotigloea are devoid of clamps but often possess well-differentiated cystidia, as well as long, cylindrical-fusiform basidiospores. Bourdotigloea encompasses nine species, of which six are described here as new.