Xanthagaricus pakistanicus sp. nov. (Agaricaceae): fi rst report of the genus from Pakistan

Abstract

Xanthagaricus pakistanicusis described as a new species from lowland northern Pakistan, based on morphological andmolecular data. It is characterized by a yellowish pileus, covered with dark brown squamules, a stipe with yellowish fibrils, globosebasidiospores, and pileal squamules made up of pseudoparenchymatous epithelium with encrusted walls. Molecular phylogenetic treeswere inferred based on nucleotide sequences of the internal transcribed spacer (ITS1-5.8S-ITS2) region and 28S nuclear ribosomalDNA. In phylogenetic analyses the genusHymenagaricussensu lato (s. l.) was inferred as a nonmonophyletic group and recoveredin two monophyletic clades, consisting of species of the generaXanthagaricusandHymenagaricussensu stricto (s. str.). On accountof the pileal squamule structure (pseudoparenchymatous epithelium) and yellowish basidiospores, and the phylogenetic position intheXanthagaricusclade the new speciesX. pakistanicusbelongs to the genusXanthagaricus . Morphoanatomical comparison with theknown species ofXanthagaricusis provided. We also made six new combinations inXanthagaricus :X. calicutensis ,X. epipastus ,X.ochraceoluteus ,X. rufomarginatus ,X. subaeruginosus , andX. taiwanensis . With this study the number of known species in the genusXanthagaricusincreases to 19.