Dirina massiliensis Durr. & Mont. forma massiliensis Taxon méditerranéen des murs calcaires.

    Thallus crustose, thick, very uneven with a verrucose to humpy surface, pale grey-brownish, whitish dull, earthy, prothallus thin, light brownish. Apothecia more or less numerous, 1-2 mm diam., sessile, greyish disc, very pruinose, more or less flexuous exciple, concolour to the thallus. Ascospores colourless, quite lengthly ellipsoid, 3-5-septed, 20-25 x 4-6 µm. Photobiont : Trentepohlia (visible in orange when cortex is damaged or eroded). Cortex and apothecia: K-, C+ pink, KC+/- fleeting red, P-. Thermophilic species not very rare on sheltered and dry walls built of limestone in the Mediterranean region, also on hard limestone rocks by the sea. Frequently combined with its soradiate form: Dirina massiliensis forma sorediata Taxon méditerranéen des murs calcaires. Very often parasited by Lecanographa grumulosa.

N.B. It may be that the specimens with yellowish thallus from Ibiza are in fact saxicolous Dirina ceratoniae that only a DNA study (not carried out) could confirm because there are Dirina ceratoniae on Pinus in the immediate vicinity.