Abstract
Lecideoid lichen-forming fungi are a large, heterogeneous group that includes many species described during the nineteenth century that are of unclear taxonomic status. We revise such a group, the species of which have previously been treated under the much-misunderstood names Catillaria contristans or Toninia squalescens , and use a seven-locus phylogeny to determine its phylogenetic position. We found strong support for a previously unrecognized monophyletic lineage within the Sphaerophoraceae , comprising five phylogenetic species, and describe the new genus Gilbertaria to accommodate them. The new genus is characterized by a crustose growth form, 1-septate ascospores, thick ((1.5–)2–3(–4) μm wide) paraphyses and asci of the Biatora -type. We revise the nomenclature and give new delimitations and descriptions of the Northern Hemisphere species Gilbertaria contristans comb. nov., G . holomeloides comb. nov., G . squalescens comb. nov. and describe the new species G . astrapeana from the Falkland Islands.