Synonyms: Lecanora pleiospora J. Steiner; Lecanora pleiospora J. Steiner f. diluta J. Steiner
Description: Thallus crustose, episubstratic, continuous to verruculose, white or yellowish white, more rarely greenish grey, epruinose, sometimes delimited by a black prothalllus. Apothecia lecanorine, adnate to sessile, 0.5-1.6 mm across, with a red-brown to blackish brown, epruinose to slightly grey-pruinose, flat to slightly convex disc and a persistent, smooth or verrucose to slightly crenulate thalline margin. Thalline exciple corticate, the cortex poorly developed, 20-40 μm thick laterally, 30-60 μm thick basally, hyaline to yellowish, inspersed with small crystals, the medullary part with large crystals dissolving in N but not in K; proper exciple colourless, with small crystals, 10-15 μm thick; epithecium reddish brown to yellowish brown, 10-15 μm high, with crystals dissolving in K; hymenium colourless, 65-85 μm high; paraphyses simple or sparingly branched, c. 2 μm thick at mid-level, the apical cells slightly swollen; hypothecium colourless. Asci (8-)12-16-spored, clavate, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid to broadly ellipsoid, rounded at apices, 10-15(-17) x (5-)6-9 μm. Photobiont chlorococcoid. Spot tests: K+ yellow, C-, KC–, P+ pale yellow. Chemistry: atranorin and chloroatranorin.
Note: widespread, but not common in the South European mountains, this epiphytic species of well-lit habitats is known from several stations across the Alps, outside Italian territory; to be looked for in Italy.