Synonyms: Lecidea alboradicata B. de Lesd.; Lecidea bullata auct. non (Körb.) Th. Fr. nec Meyen & Flot.; Lecidea contorta Bagl. & Carestia; Lecidea lacticolor Arnold; Lecidea mesotropiza Nyl.; Lecidea nansenii Lynge; Lecidea subdita Nyl.; Lecidella bullata auct. non Körb.
Description: Thallus crustose, episubstratic, white to grey-white, consisting of convex, to 1.5 mm wide granules with an eroded surface. Apothecia cryptolecanorine to lecideine, to 1.5(-3) mm across, almost immersed in the thallus to subsessile, round to irregular in outline, with a flat to convex, black but usually grey-pruinose disc, a soon excluded, usually inapparent thalline margin, and a black, at first prominent, later excluded proper margin. Proper exciple dark brown in section, usually extending below the hypothecium; epithecium with crystals dissolving in K; hymenium colourless, 40-70(-90) µm high, without crystals; lower part of hypothecium densely filled with crystals soluble in K. Asci 8-spored, clavate, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, 7-12 x 5-8 µm. Photobiont chlorococcoid. Spot tests: thallus K+ yellow, C-, KC+ yellow, P+ deep yellow. Chemistry: atranorin, zeorin, and variable amounts of psoromic and 2’-0-demethylpsoromic acids. Note: on slightly underhanging surfaces of siliceous rocks, especially crystalline schist, in humid and cold situations in the alpine and nival belts of the Alps, often starting the life-cycle on other crustose lichens. Growth form: Crustose Substrata: rocks Photobiont: green algae other than Trentepohlia Reproductive strategy: mainly sexual In underhangs rarely wetted by rain