Species recognition in Pluteus and Volvopluteus (Pluteaceae, Agaricales): morphology, geography and phylogeny

The phylogeny of several species-complexes of the genera Pluteus and Volvopluteus (Agaricales, Basidiomycota) was investigated using molecular data (ITS) and the consequences for taxonomy, nomenclature and morphological species recognition in these groups were evaluated. Conflicts between morphological and molecular delimitation were detected in sect. Pluteus, especially for taxa in the cervinus-petasatus clade with clamp-connections or white basidiocarps. Some species of sect. Celluloderma are apparently widely distributed in Europe, North America and Asia, either with (P. aurantiorugosus, P. chrysophlebius, P. fenzlii, P. phlebophorus) or without (P. romellii) molecular differentiation in collections from different continents. A lectotype and a supporting epitype are designated for Pluteus cervinus, the type species of the genus. The name Pluteus chrysophlebius is accepted as the correct name for the species in sect. Celluloderma, also known under the names P. admirabilis and P. chrysophaeus. A lectotype is designated for the latter. Pluteus saupei and Pluteus heteromarginatus, from the USA, P. castri, from Russia and Japan, and Volvopluteus asiaticus, from Japan, are described as new. A complete description and a new name, Pluteus losulus, are given for the African P. cervinus var. ealaensis. The American Volvopluteus michiganensis is described in detail. Taxonomic comments and a morphology-based key to all known species of Volvopluteus are provided.