Dirina massiliensis Durr. & Mont. forma sorediata (Müll. Arg.) Tehler Taxon méditerranéen des murs et des rochers calcaires.

    Thallus crustose, 2-8 cm diam., thick, warty to bumpy, finely powdery, dull whitish, earthy whitish, white-greyish, covered by punctiform to granulose soralia, greyish, grey-brownish, prothallus more or less wide but almost always present, pale brownish, beige. No apothecia. Photobiont : Trentepohlia. K-, C+ red (slow), KC+ red, Pd-. Warm species, characteristic of old sheltered walls made of limestones from Mediterranean region.

N.B. Atlantic taxa on poorly acid old walls or on mortar or concrete seem to belong to different populations, see : Dirina massiliensis forma sorediata Taxon atlantique des murs en pierre peu acides ou en ciment of poorly acid stone or mortar walls.