Aquacidia, a new genus to accommodate a group of skiophilous temperate Bacidia species that belong in the Pilocarpaceae (lichenized ascomycetes)

The new genus Aquacidia is proposed to accommodate three temperate Bacidia species that belong in the Pilocarpaceae and are not related to the type species B. rosella, which is in the Ramalinaceae. The phylogenetic position was clarified by an analysis of the mtSSU region showing a distinct lineage within the Pilocarpaceae. The following new combinations are proposed: Aquacidia antricola (Hulting) Aptroot (syn. Bacidia antricola, B.carneoglauca), A. trachona (Ach.) Aptroot, and A. viridifarinosa (Coppins & P. James) Aptroot. A key to Aquacidia species is provided.