Syn.: P. faginea auct.

Corticolous, on all kinds of trees along roads or inside forests, exceptionally saxicolous, on exposed, siliceous rocks.

Belgium: Camp.: AR, Mosan: AR, Ard., Lorr.: C.

Luxembourg: Ard.: CC, Lorr.: C.

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

Two chemical strains have been observed: with, and without protocetraric acid, the latter being the rarest.

Lit.: Boul.: 71, Ba: 10, Di: 186, Mü1: 150, NL84: 16.