Terricolous lichens of the western Padanian Plain: New records of phytogeographical interest

Very little is known of the earlier lichen flora of the Padanian Plain, the most heavily anthropized and industrialized part of Italy, which is currently extremely poor. Terricolous lichens in particular are the most sensitive to threats, and have almost totally disappeared from the western Padanian Plain. This paper reports new findings of 20 terricolous lichen species, several of which are rare or poorly known in Italy or are of some phytogeographical interest because they are found at lower altitudes than their usual distribution (i.e. Cladonia coccifera, Cladonia uncialis). In addition, Cladonia humilis is new for Lombardy and two other species, Cladonia portentosa and Stereocaulon condensatum, are reported for the second time in the same region. The significance of these species is discussed with regard to their historical records from the same area and their current altitudinal distribution; they were probably much more widespread in the past, but the decline and disappearance of their habitats in lowland areas have been followed by their own disappearance in many localities. A modification of the rarity status of some of these species in the considered phytoclimatic belts, based on the new records, is proposed.