Saxicolous on siliceous rocks, usually in exposed conditions, on natural outcrops or in artificial habitats, incl. walls, debris in disused quarries, railway ballast, etc.

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

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

France: Mosan: RRR, Ard.: RR, Lorr.: RR.

Lit.: Mü1: 152, NL77: 21, NL92: 170, Zwaenepoel et al. (1994: 37).