This paper presents the results of a 7 year-long study on the lichen flora and vegetation of 16 archaeological sites located in the Provinces of Rome and Viterbo (Central Italy, Latium). The lichen flora on monuments consists of 284 taxa at infrageneric level (276 species and 8 infraspecific taxa). The temperate element constitutes 45% of the flora; the species with Southern distribution in Europe are 20.4%, suboceanic species 10% of the total. The Northern element (in respect with the survey area) constitutes 10% of the flora, but is composed by species which are very rare in the survey area. The vegetational study is based on 148 phytosociological releves. The matrix of species and releves has been submitted to numerical classification and ordination. The results permit to distinguish several lichen communities. The ecology of each community and the damage caused to the monuments are discussed on the basis of indirect ecological data (ecological indexes as proposed by Wirth, 1980).
The paper includes a key for the identification of the lichen taxa recorded in the survey area.