Morphological and molecular confirmation of the first finding of Leccinum duriusculum (Boletaceae, Boletales) in the glacial rocky mountains of Hunza Valley (Central Karakorum), Gilgit, northern Pakistan.

The of slate bolete Leccinum duriusculum is reported for the first time from Pakistan based on morphological, scanning electron microscopical, ecological and phylogenetic evidences. Sampling was done from glacial rocky mountains of Hunza valley (Central Karakorum), Gilgit, Northern Pakistan, dominated by Populus alba trees at their foothills. Populus trees are the ectomycorrhizal partners of Leccinum duriusculum. A comprehensive description of the macro- and micro-morphological characteristics is included, supplemented with color photographs of fresh basidiomata in their natural habitat and microscopic images with main anatomical features. Phylogenetic analysis of the studied sample was conducted using internal transcribed spacer (ITS) and larger subunit (LSU) sequences of nuclear ribosomal DNA. This analysis supports the taxonomic identification of Leccinum duriusculum and confirms its phylogenetic position. Additionally, comparisons are made with closely related taxa that exhibit phenotypic and molecular genetic similarities. To our knowledge, this represents the first record of this taxon occurring in Pakistan.