On exposed, calcareous rocks, including sandstone, mainly in natural conditions.

Belgium: Fl.: RRR, Brab.: RRR, Mosan: R.

Luxembourg: Lorr.: RR.

France: Lorr.: RRR.

Lit.: Ertz: 20, NL84: 17, NL97: 55, Giralt et al. (1997: 115-118).