On calcareous and sandstone rocks, on vertical surfaces in shaded habitats.

Belgium: Mosan: AR, Ard.: RRR, Lorr.: RR.

Luxembourg: Lorr.: AR.

France: Lorr.: RRR.

The distinction of this species from O. varia requires further studies.

Lit.: L5: 33, NL84: 16, NL92: 172.