Arthonia didyma Körb.

Syn.: Arthonia aspersella Leight., Arthonia atrofuscella Nyl., Arthonia pineti Körb., Caldesia didyma (Körb.) Trevis.
Lichenised.
Substrate: bark
Altitudinal range: from the submediterranean/colline belt (potential vegetation: mixed deciduous forests dominated by Quercus and Carpinus) to the montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies)
Note: a cool-temperate species found on smooth bark in humid areas.
Austria: Vorarlberg; Tirol; Salzburg; Kärnten; Steiermark; Oberösterreich; Niederösterreich (incl. Wien); Burgenland; Germany: Oberbayern; Schwaben; Switzerland: Bern; Glarus; Graubünden; Schwyz; Ticino; Uri; Unterwalden; Vaud; Valais; France: Alpes-Maritimes; Drôme; Isère; Var; Italy: Veneto; Trentino Alto Adige; Lombardia; Piemonte; Slovenia: Alpine and Pre-Alpine Slovenia; Trnovsky Gozd;