Description: Thallus crustose, ecorticate, endolithic to (very rarely) thinly episubstratic, smooth, effuse, pale grey to brownish grey, often with a pinkish tinge when fresh. Perithecia black, 0.5-0.8 mm across, one quarter- to half-immersed, conical-hemispherical, often flattened and with distinct papillose ostioles. Involucrellum spreading outwards from the exciple; exciple colourless; hymenial gel I-, K/I-; pseudoparaphyses persistent, slender, sparingly branched or anastomosing, long-celled; periphyses absent. Asci 8-spored, narrowly cylindrical, K/I-, fissitunicate, the apical dome with a broad ocular chamber surmounted by a hemispherical meniscus-like structure. Ascospores 1-septate, not or slightly constricted at septum, the septum thick and the cells equal, hyaline, ellipsoid with rounded or rarely pointed ends, 12-13 x 5-6 μm, uniseriately arranged in the asci, surrounded by a perispore which appears verrucose in water, smooth in K. Photobiont trentepohlioid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a taxon characterised by the small spores; only known from the type locality in the Italian Alps, where it was found on fissures of marble.