Parmotrema reticulatum forme saxicole.

      This form is characterized by its occurrence on the rocks of heathlands, it is often well developed.

_ It should not be confused with Parmotrema robustum saxicolous form which can occur in the same habitat but which has smaller marginal soralia and which is K+ dirty yellow, and especially with Parmotrema perlatum saxicolous form whose soredia are smaller and more globose, K+ yellow not turning red and which usually has marginal hairs.