Evernia prunastri var. herinii (Duv.) Maas Gest.

   The main difference with Evernia prunastri var. prunastri is the lack of usnic acid, inducing a very pale grey colour, without yellow-green tinges. This taxon has an imperfectly defined status (see the high number of synonyms), and is much scarce than the type; it probably exists in our prospection area but has not been clearly distinguished from the type growing there, probably in combination.