On siliceous and sandstone rocks, often over mosses, or over basic bark, always in sheltered and humid conditions; the only recent specimen on a vertical, siliceous rock by a river at 30 cm above water level.

Belgium: Mosan: RR (2005), Ard.: R (†1966), Lorr.: RRR (†1968).

Luxembourg: Ard.: RRR (1991), Lorr.: R (†<1850).

France: - .

Lit.: L4: 18, La66: 283-286, Ertz & Duvivier (2006: 51), Diederich (1986a: 120), Schlechter (1995: 470).