On soil over natural, calcareous and siliceous outcrops, also found in artificial habitats like old walls, very rare on trunks.

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

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

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

Lit.: Ca: 178, DSL: 235, La69: 139, NL84: 13.