Protoparmeliopsis muralis var. diffracta (Ach.) M. Choisy ex Werner

      Differs from the type of Protoparmeliopsis muralis var. muralis by its loose lobes, sometimes bordered with blackish-grey, revealing the black hypothallus between them. Thermophilic and heliophilous variety growing on very exposed siliceous rocks.

Cf. Protoparmeliopsis bolcana with a more greenish-yellow thallus and larger and fewer apothecia not grouped together in the center