Syn.: Aspicilia radiosa (Hoffm.) Poelt & Leuckert, Lecanora radiosa (Hoffm.) Schaer., L. subcircinata Nyl., Placodium circinatum (Pers.) Gray

On hard calcareous rocks, especially common in nitrophilous conditions, in natural and artificial habitats.

Belgium: Fl.: RRR, Brab.: RRR, Mosan: AC (locally common), Ard.: RRR, Lorr.: RRR.

Luxembourg: Lorr.: R.

France: Mosan: RR, Lorr.: R.

Lit.: Ertz: 20, La69: 105, NL77: 19, NL84: 12, NL92: 171, NL97: 51.