On siliceous or sandstone, rarely calcareous rocks or stones, always in streams.

Belgium: Mosan: RR, Ard.: RR.

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

France: - .

Lit.: Mü1: 140, NL77: 23, NL84: 18, NL87: 23, Molitor & Diederich (1997: 81-82).