Description: Thallus crustose, episubstratic, rather thick, rimose or rimose-areolate, smooth or slightly granulose, white, without a distinct prothallus. Apothecia rounded to ellipsoid, 0.5-1 x 0.3-0.5 mm, simple or sparingly branched, with an expanded, bluish grey-pruinose disc. Proper exciple black, carbonized, not extending below the hymenium; epithecium brownish, 20-35 μm high; hymenium colourless, 60-100 μm high, I+ blue; paraphysoids branched and anastomising, c. 1.5 μm thick, the apical cells hardly slwollen; subhymenium and hypothecium colourless to pale yellowish brown. Asci 8-spored, clavate, the inner layer of endoascus amyloid in upper part, with a I+ blue ring visible around a small ocular chamber, Varia-type. Ascospores 3-septate, at first hyaline but turning brown at maturity, ellipsoid, often slightly pointed at one end, 13-16 x (4-)5-6.5 μm, with a 1-1.2 μm thick gelatinous perispore. Pycnidia black, immersed. Conidia bacilliform, straight, 5-6 x c. 1 μm. Photobiont trentepohlioid. Spot tests: thallus K-, C-, KC- P-, UV-. Chemistry: without lichen substances.
Note: a calcicolous coastal species known from North Africa and southern France; to be looked for in Italy.