The <i>Pluteus leoninus</i> clade in the Holarctic region: existing names evaluated and seven new species described

<i>Pluteus leoninus</i> 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 <i>P. leoninus</i> 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 <i>P. leoninus</i>, 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, <i>tef1</i>), ecological, and geographic variation in our data set, we recognize 12 holarctic species, six in Eurasia (<i>P. favrei, P. leoninus, P. roseipes, P. ochraceoleoninus</i>, sp. nov. <i>P. ussuriensis</i>, sp. nov. <i>P. variabilicolor</i>) and six in North America (<i>P. aureus</i>, sp. nov. <i>P. croceus</i>, sp. nov. <i>P. flavofuligineus, P. hesperius</i>, sp. nov. <i>P. insularis</i>, sp. nov. <i>P. pumae</i>, sp. nov.). Tropical species included by Singer in stirps <i>Leoninus</i> are briefly discussed: <i>P. chrysaegis</i>, 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 <i>P. conizatus</i>, originally described from Sri Lanka, which is confirmed to be part of <i>Pluteus</i> sect. <i>Hispidoderma</i> but does not belong in the /leoninus clade.