Identifying and naming the currently known diversity of the genus <i>Hydnum</i>, with an emphasis on European and North American taxa

In this study, 49 species of Hydnum are recognized worldwide. Twenty-two of them are described here as new species. Epitypes are proposed for H. repandum and H. rufescens. The majority of the species are currently known only from a single continent. The barcodes produced in this study are deposited in the RefSeq database and used as a basis to name species hypotheses in UNITE. Eleven infrageneric clades recovered in a phylogenetic analysis are supported by morphological characteristics and formally recognized: subgenera Alba, Hydnum, Pallida, and Rufescentia; sections Hydnum, Olympica, Magnorufescentia, and Rufescentia; and subsections Mulsicoloria, Rufescentia, and Tenuiformia.