Saxicolous, very frequent on sandstone rocks (especially inside forests), sometimes on walls (incl. in cities), also on other calcareous or on siliceous rocks, in humid forests rarely on the bark of old Fagus or Quercus trees.

Belgium: Mosan: AR, Ard.: R (locally common in the Semois valley).

Luxembourg: Ard.: RRR, Lorr.: AC.

France: Ard.: RRR, Lorr.: RRR.

Lit.: Di: 150, Ertz: 19, NL84: 15, NL92: 157-158, NL97: 50.