Verrucaria ruderum DC.

Syn.: Amphoridium ruderum (DC.) Servít
Lichenised. Poorly known taxon.
Substrate: calciferous rocks
Altitudinal range: from the submediterranean/colline belt (potential vegetation: mixed deciduous forests dominated by Quercus and Carpinus) to the subalpine belt (potential vegetation: open, taiga-like forests dominated by Larix decidua and/or Pinus cembra and Rhododendron)
Note: mostly on walls made of mortar and cement; perhaps a synonym of other species, with a few scattered records from the Alps.
Austria: Steiermark; France: Isère; Vaucluse; Italy: Veneto; Lombardia; Valle d'Aosta;