The genus Phellodon (Thelephorales, Basidiomycota) in Europe: Four new species, one new combination, four new typifications and a first European record.

Abstract

Phellodon is a globally distributed genus of stipitate hydnoid fungi recognised by a white spore print and an ectomycorrhizal life strategy. In Europe, many Phellodon species have declining populations and are used as indicators of forests with high conservation values. However, their use in this context and the correct assessment of their extinction risk, according to IUCN guidelines, are currently hampered by inconsistent name usage and unclear species delimitations, primarily within the species complexes of P. melaleucus, P. niger and P. tomentosus. We analysed 286 ITS sequences of Phellodon, of which 51 were also analysed in conjunction with the corresponding LSU regions. This work included 102 newly sequenced collections, primarily sourced from Sweden and the UK. Our phylogenetic results show that four species are new to science and hence we formally describe P. castaneoleucus within the P. melaleucus morphological complex, P. aquiloniniger and P. frondosoniger within the P. niger complex and P. dititomentosus as a sister species to P. tomentosus. The combination P. melilotinus is made to accommodate an additional, previously described, species that belongs in the P. niger complex. We designate lectotypes and epitypes for P. melaleucus, P. niger and P. tomentosus as well as an epitype for P. melilotinus. Phellodon ellisianus is recorded as new to Europe and the ecological amplitude of P. secretus and P. violaceus is revealed to be wider than previously believed. We provide a key to all 13 species currently known in Europe and assign them to three habitat-based assemblages based on data from the Nordic countries and the UK. We hope this will facilitate the assessment of such habitats for legal protection and other conservation-related actions. Citation: Svantesson S, Larsson E, Larsson K-H, Parfitt D, Suz LM, Ainsworth AM (2025). The genus Phellodon (Thelephorales, Basidiomycota) in Europe: Four new species, one new combination, four new typifications and a first European record. Fungal Systematics and Evolution 15: 1-45. doi: 10.3114/fuse.2025.15.01.