DNA barcoding and morphological studies reveal two new species of waxcap mushrooms (Hygrophoraceae) in Britain

Rigorous diagnostics and documentation of fungal species are fundamental to their conservation. During the course of a species-level study of UK waxcap (Hygrophoraceae) diversity, two previously unrecognized species were discovered. We describe Gliophorus europerplexus sp. nov. and G. reginae sp. nov., respectively orange–brown and purple–pink waxcap mushrooms, from nutrient-poor grasslands in Britain. Both share some morphological features with specimens assigned to Gliophorus (=Hygrocybe) psittacinus. However, analysis of sequences of the nuclear ITS DNA barcode region from these and related taxa confirms the phylogenetic distinctness of these lineages. Furthermore, we demonstrated that the holotype of Hygrophorus perplexus, a North American species morphologically resembling G. europerplexus, is phylogenetically divergent from all our collections. It is likely that further collections of G. europerplexus will be revealed by sequencing European material currently filed under G. perplexus and its synonyms. However, two such collections in the Kew fungarium yielded sequences that clustered together but were divergent from those of G. europerplexus, G. perplexus and G. psittacinus and may represent a further novel taxon. By contrast, G. reginae is morphologically distinct and can usually be recognized in the field by its purplish viscid pileus and relatively stout, flexuose, pale stipe. It is named to commemorate the diamond jubilee of Her Majesty Queen Elizabeth II in 2012 and the 60th anniversary of her coronation in 2013