Description: Thallus crustose, endosubstratic and not evident. Medullary hyphae I+ intensively blue. Apothecia lecideine, black, rounded in outline, up to 0.5-1,1(-1.5) mm across, sessile and more or less constricted at base, with a concave to flat, not umbonate disc, and a rather thick, raised, sometimes flexuose, persistent or rarely finally excluded proper margin. Proper exciple grey, 50-150 µm wide laterally, without crystals; epithecium green to usually intensively blue-green; hymenium colourless, 35-55 µm high, I+ blue; paraphyses coherent; subhymenium colourless, 0-70 µm high; hypothecium colourless or pale emerald green. Asci 8-spored, clavate, Lecidea-type. Ascospores 1-celled, hyaline, ellipsoid or oblong, (5-)6.6-10.6(-13.5) x (2.5-)3.1-4(-5) µm, 1.9-3 times as long as wide. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-. Chemistry: without lichen substances.
Note: on siliceous rocks, with optimum in the alpine belt; known with certainty from the Western Alps (France); to be looked for in the Italian Alps.