Distribution: N - TAA (Nascimbene 2008b), Lig (Giordani & al. 2016). C - Tosc. S - Camp (Aprile & al. 2003b), Cal (Puntillo 1996), Si (Ottonello & Salone 1994).
Description: Thallus crustose, endosubstratic or thinly episubstratic, whitish to pale brownish grey, thin, smooth, rimose or granular. Perithecia black, 0.7-1.5 mm across, one quarter- to half- immersed. Involucrellum black, tightly incurved around the exciple and often completely surrounding it; exciple globose, colourless or pale brownish; hamathecium of persistent, slender, sparingly branched, long-celled pseudoparaphyses; periphyses absent; hymenial gel I-, K/I-. Asci 8-spored, cylindrical, K/I-, fissitunicate, the apical dome with a broad ocular chamber surmounted by a hemispherical meniscus-like structure. Ascospores 1(-3)-septate, hyaline, ellipsoid with rounded ends, (17-)20-35 x (9-)10-15 μm, uniseriately arranged in the asci, surrounded by a perispore which appears verrucose in water, smooth in K. Pycnidia rather rare, black, 0.2-0.3 mm across. Conidia 1-celled, hyaline, ellipsoid. Photobiont trentepohlioid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: an apparently Mediterranean-Atlantic, mild-temperate species ranging from Macaronesia to Norway, but also known from central Europe, found on soft calcareous substrata (mortar, calciferous sandstone) in warm-humid areas below the montane belt. Mostly Tyrrhenian in Italy, but also reported from the Alps.
Growth form: Crustose
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)