Caloplaca citrina (Hoffm.) Th. Fr.

Syn.: Amphiloma citrinum (Hoffm.) Müll. Arg., Blastenia citrina (Hoffm.) B. de Lesd., Callopisma citrinum (Hoffm.) A. Massal., Flavoplaca citrina (Hoffm.) Arup, Frödén & Søchting, Lecanora citrina (Hoffm.) Ach., Lichen citrinus (Hoffm.) Ach., Placodium citrinum (Hoffm.) Hepp, Pyrenodesmia citrina (Hoffm.) Trevis., Verrucaria citrina Hoffm.
Lichenised.
Substrate: calciferous rocks, lignum
Altitudinal range: from the mesomediterranean belt (potential vegetation: evergreen broad-leaved forests dominated by Quercus ilex) to the alpine belt (potential vegetation: treeless Alpine grasslands and tundras, to the lower limit of perennial snow and the equilibrium line of glaciers)
Note: C. citrina is often claimed to be an almost cosmopolitan lichen. However, after a recent molecular revision of the entire complex, it seems that the species has a rather restricted distribution centered in Central Europe. The species complex, which still needs a thorough revision in the Alps, occurs on a wide variety of substrata, from asbestos-cement, concrete and mortar to basic siliceous rocks or even eutrophicated wood, being very tolerant to, and even favoured by eutrophication (e.g. urine-deposits). Several records could refer to other species in the complex.
Austria: Vorarlberg; Tirol; Salzburg; Kärnten; Steiermark; Oberösterreich; Niederösterreich (incl. Wien); Burgenland; Germany: Oberbayern; Schwaben; Switzerland: Bern; Graubünden; Luzern; Schwyz; Valais; France: Alpes-de-Haute-Provence; Haute-Alpes; Alpes-Maritimes; Drôme; Isère; Savoie; Haute-Savoie; Vaucluse; Var; Italy: Friuli; Veneto; Trentino Alto Adige; Lombardia; Piemonte; Valle d'Aosta; Liguria; Slovenia: Alpine and Pre-Alpine Slovenia;