Abstract
The fungal genus Agaricus includes edible, medicinal and some toxic species mainly in the Agaricus sect. Xanthodermatei. As the diversity of the genus is not well known in Iran, an inventory of the species has begun in 2013 in different provinces. Morphological and/or molecular analyses of 12 selected specimens from recent field collections and from herbarium specimens revealed that ten of them belonged to four potentially poisonous species of the Agaricus sect. Xanthodermatei: A. iodosmus, A. moelleri, A. phaeolepidotus and A. xanthodermus. Moreover, our study revealed that previous first records of A. xanthodermus and A. moelleri in Iran had been based on morphologically misidentified and correctly identified specimens, respectively. Finally, three species, A. iodosmus, A. phaeolepidotus and A. xanthodermus are reported as new records for Iran mycobiota. The four species of the section are described and illustrated.