Distribution: N - TAA, Piem (Isocrono & al. 2004), VA (Piervittori & Isocrono 1999). C - Sar (Nöske 2000).
Description: Thallus crustose, episubstratic, continuous to rimose-areolate, pale grey to bluish grey, of (0.3)0.4-1(-1.8) mm wide, rounded or minutely lobed, flat to slightly convex areoles scattered on a black hypothallus. Medulla white, I-. Apothecia lecideine, (0.2-)0.5-0.7(-1) mm across, at first immersed in the areoles then slightly prominent, usually 1 per areole, with a dark brown to black, mostly flat disc, and a very thin, poorly evident and soon excluded proper margin. Proper exciple poorly developed, thin, dark brown to olive-brown in outer part, of radiating hyphae; epithecium brown; hymenium colourless to yellowish, 50-65 µm high, I+ blue; paraphyses sparingly branched and more or less anastomosing, 1.5-2 µm thick at mid-level, the apical cell clavate, 3-4.5 µm wide, with a dark cap; hypothecium colourless, yellowish or grey. Asci 8-spored, broadly cylindrical to subclavate, more or less of the Lecanora-type, but with a weakly defined apical cushion and ocular chamber. Ascospores 1-celled, hyaline, ellipsoid to oblong, (8-)10-16(-18) x (4-)5-6(-7) µm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-. Chemistry: miriquidic acid.
Note: on moist siliceous rocks in upland areas, starting the life-cycle on yellow Rhizocarpon-species, with optimum above treeline. The identification of the samples from Sardegna is dubious.