The Pluteus leoninus clade in the Holarctic region: existing names evaluated and seven new species described.

Pluteus leoninus is a commonly reported species, characterized by a yellow pileus, yellow colors on the stipe, pleurocystidia provided with digitiform excrescences, and a pileipellis composed of long, fusiform elements. Several species related to P. leoninus have been described from the temperate and boreal areas of the Northern Hemisphere, and previous phylogenetic studies have shown that more than one species can be recognized around P. leoninus, but it was unclear how many, or which names, would be correct for them. We studied 141 holarctic collections in the /leoninus clade and available type collections of species in this group. Taking into account the morphological, molecular (ITS, tef1), ecological, and geographic variation in our data set, we recognize 12 holarctic species, six in Eurasia (P. favrei, P. leoninus, P. roseipes, P. ochraceoleoninus, sp. nov. P. ussuriensis, sp. nov. P. variabilicolor) and six in North America (P. aureus, sp. nov. P. croceus, sp. nov. P. flavofuligineus, P. hesperius, sp. nov. P. insularis, sp. nov. P. pumae, sp. nov.). Tropical species included by Singer in stirps Leoninus are briefly discussed: P. chrysaegis, originally described from Srik Lanka, is confirmed to occur in North America (Florida, Puerto Rico); we provide the first modern description and molecular data for P. conizatus, originally described from Sri Lanka, which is confirmed to be part of Pluteus sect. Hispidoderma but does not belong in the /leoninus clade.