?Incl. O. saxicola Ach.

On natural outcrops of hard calcareous rock, and on maritime sandstone rocks.

Belgium: Fl.: RRR, Mosan: R, Lorr.: RR.

Luxembourg: Lorr.: RR.

France: Mar.: RR, Boul.: RRR.

Lit.: Boul.: 63-64, NL84: 16, NL97: 52, Tonglet (1898: 37, sub O. saxicola).