Distribution: N - TAA, VA (Piervittori & Isocrono 1999).
Description: Thallus crustose, episubstratic, medium brown, areolate. Areoles 1-2 mm wide, the largest ones almost subsquamulose, with more or less free margins, contiguous to imbricate, epruinose, often irregularly sulcate. Upper cortex 20-30 μm high, brownish in upper part, colourless in lower part, the cells 3-5 μm wide, overlain with an amorphous layer of variable thickness; algal layer irregular, discontinuous, penetrating the medulla in tooth-like columns. Apothecia lecanorine, 1-2 mm across, with a flat to strongly convex, dark brown disc, and a thin to thick thalline margin. Epithecium brown; hymenium colourless, 80-140 μm high; paraphyses 1.5-2.5 μm thick at base. Asci >100-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, narrowly ellipsoid, 5-7 x 2-3 μm. Pycnidia immersed. Conidia ellipsoid, c. 3 x 1 μm. Photobiont chlorococcoid. Spot tests: thallus and medulla K-, C-, KC-, P-. Chemistry: without lichen substances.
Note: hitherto known only from dry-continental Alpine valleys, on south-facing surfaces of siliceous rocks, where it is locally common.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)