Syn.: C. murorum (Ach.) Th. Fr., Lecanora murorum (Hoffm.) Ach.

On hard calcareous rocks, usually in dry, sunny and nitrophilous conditions, mainly in natural habitats, occasionally on walls, mortar or concrete.

Belgium: Mar.: AR, Fl.: AC, Camp.: R, Brab.: AR, Mosan: AR, Ard.: RR, Lorr.: RR.

Luxembourg: Ard.: R, Lorr.: R.

France: Mar.: R, Boul.: R.

Gaya (2009) showed that the material included in C. saxicola is heterogeneous, including several species in our checklist area. One specimen from France (Picard) has been identified by Gaya as representing C. saxciola s.str., but the rest of the material still needs to be critically revised.

Lit.: Boul.: 67, Ma: 221-225, NL92: 168, NL93: 42, VGH: 114, Ertz: 19, Gaya (2009), Hoffmann & Van Rompu (1995), Zwaenepoel et al. (1994: 37).