Abstract
There are around 500 species of saprobic basidiomycetes in the genus Agaricus, of which 21 are reported from Pakistan. In this study, Agaricus karakensis sp. nov. is described as a new species from the tropical semi-arid District Karak, Khyber Pakhtunkhwa, Pakistan. The taxonomic identification was based on morphological features and ITS-region of rDNA. Both, field data and morpho-anatomical characterizations support that our specimens belong to a new species of Agaricus section Bivelares from family Agaricaceae, order Agaricales. In the phylogenetic tree, A. karakensis fall in section Bivelares forming a sister branch with A. bitorquis. In this paper, the nearest falling species were also compared with our novel finding in morphology.