The present work is a taxonomic study within the family Megasporaceae; an overview is given on history, phylogeny, taxonomy, description, delimitation and taxonomic revision of some Megasporaceae genera and species. The genus Aspiciliella is reintroduced on the basis of phylogenetic and morphological studies from a wide geographical range including Iran, Caucasia, Greece and Macaronesia. The new species Aspiciliella portosantana and the new combination Aspiciliella cupreoglauca (B.de Lesd.) Zakeri et al. is proposed. We identified a total of six species-level lineages in the Aspiciliella intermutans complex using gene concatenation and coalescent-based species tree approaches. The corticolous species Megaspora cretacea is described as new for science. Furthermore, a lectotype for Aspicilia reticulata and a neotype for Aspiciliella cupreoglauca were designed, and A. reticulata was synonymised with A. cupreoglauca. Some new records of Megasporaceae from Armenia are reported.