An improved phylogeny and revised taxonomy of Catillariaceae (Lecanoromycetes, Ascomycota)

Abstract The boundaries of the family Catillariaceae have largely remained untested through phylogenetic methods. Recent studies have led to the transfer of several genera previously classified in Catillariaceae to the newly described family Leprocaulaceae. Despite these changes, the distinction between Catillariaceae, Leprocaulaceae, and Catinariaceae remains ambiguous. To address these uncertainties, we conducted a comprehensive phylogenetic analysis with improved taxon sampling (including the type species of all genera) and a six‐marker dataset, including two newly developed markers. Our results strongly support Catillariaceae as a monophyletic group including the currently accepted genera Catillaria , Catinaria , Halecania , Leprocaulon , Solenopsora , and Speerschneidera . Consequently, we synonymize Catinariaceae and Leprocaulaceae with Catillariaceae, resulting in a revised, morphologically cohesive circumscription. The redefined Catillariaceae includes all Lecanoromycete species characterised by a Catillaria ‐type ascus, paraphyses with thickened brown pigmented caps, and 2‐celled, unpigmented ascospores (in sexually reproducing species). However, our findings question traditional generic circumscriptions in this group, revealing paraphyly in Catillaria , Halecania , Leprocaulon , and Solenopsora . As a step towards resolving these issues, we describe the new genera Caelochroma (for Catillaria atomarioides ) and Halecaniella (for Halecania viridescens ), and resurrect the genera Microlecia (for Catillaria lenticularis ) and Placolecania (for part of Solenopsora not including its type). Several taxonomic challenges persist however, particularly within Leprocaulon and Solenopsora s.l. Additionally, we demonstrate that the genus Placolecis does not belong in Catillariaceae. We describe Halecania abscondita , a new corticolous species from northern Sweden, propose the new combination Catillaria nubila (for C . chalybeia var. chloropoliza ) and designate a lectotype for Lecania alpivaga .