The distribution of sorediate lichens in different ecological scenarios is depicted on the basis of data obtained from ITALIC, an on-line database on the lichens of Italy. Sorediate species are ca. 15% of the Italian flora. They are most frequent under humid-shaded conditions, and – limited to certain types of substrata – under moderate to high levels of eutrophication. Most of the sorediate species of Italy are relatively rare, only a few are abundant in anthropized habitats. It is suggested that the presence of sorediate species is highest under the same conditions which favour the proliferation of free-living algae.