Corticolous, mostly on the smooth bark at the base of old Quercus in shaded forests, rarely on the bark of Corylus and other trees.

Belgium: Mar.: RRR, Fl.: RR, Camp.: RR, Brab.: AR, Mosan: AR, Ard.: AR (locally common), Lorr.: R.

Luxembourg: Ard.: R, Lorr.: AC.

France: Mar.: RR, Boul.: R, Pic.: RR, Lorr.: RRR.

Lit.: Boul.: 66, Di: 42, Ho:101, 104, 564, NL84: 11.