On calcareous, natural outcrops, and on artificial substrates (walls or concrete), exceptionally on wood.

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

Luxembourg: Lorr.: AC.

France: Mar.: AR, Boul.: R, Lorr.: R. Probably overlooked and common in most districts.

Lit.: Boul.: 73, Ertz: 43, Mü1: 140, NL77: 23, NL84: 18, NL87: 23, NL92: 165, NL97: 57.