Lichens of the Hassan Tower Monument (Rabat, Morocco)

This paper describes the lichen species that colonize thewalls of the Hassan Tower, a historical monument of Morocco.The lichen species identified as Caloplaca flavescens, C.Vitellinula, Rocella phycopsis and Xanthoria calcicola are distributeddifferently on the walls of the tower. In addition to otherenvironmental factors, such lichen species encountered areinvolved in one way or another in the deterioration of buildingmaterials of the Hassan Tower.