Dirina massiliensis Durieu & Mont. forma massiliensis  Taxon méditerranéen des rochers calcaires.

    Thallus 1-3 mm thick, smooth to minutely rough, sometimes slightly pruinose, chalk-white, whitish with orange spots in thin or eroded sections owing to the Trentepohlia photobiont, prothallus whitish. Apothecia usually numerous, sessile, base narrowed, sometimes distorted, 1-3 mm diam., disc greyish more or less below a thick whitish pruine, exciple thick, wavy, concolourous to the thallus. Ascii 8-spored, 100-110 x 16-20 µm according to our measures.  Ascospores  colourless, narrowly ellipsoid, straight to slightly curved, 3-septate,  20-24 x 4-6 µm according to the literature, 21-27 x 4-6 µm according to our measures. Photobiont: Trentepohlia. Cortex: C+ pink-red, CK+/- red, K-, Pd- ; medulla: C- (seldom pink), CK- (seldom pink), K-, Pd-. Strong mediterranean and maritime trends, on vertical calcareous rocks near the seashore, protected from direct rain.

N.B. Dirina massiliensis forma sorediata Taxon méditerranéen des murs et des rochers calcaires might be a sterile sorediate form, more continental or more atlantic. Fertile atlantic forms may belong to different populations: see  Dirina fallax forma fallax Taxon atlanfique.

N.B. There is another more common morph, more dark brown-greyish, also mediterranean, on more humid, sheltered and little-lit calcareous rocks rather far from the sea: Dirina massiliensis forma massiliensis Taxon méditerranéen des rochers calcaires abrités.

Pictures presented here were taken from Jacques HAINE's herbarium, collected in 1976 by Robert ISERENTANT from the Leuven Catholic University on Riou island, Marseille, and assigned to the Dirina repanda species. It seems possible to consider these photographs as representing Dirina massiliensis ss str.