Description: Thallus crustose to subsquamulose, episubstratic, continuous, dark green to dark olive-brown, of more or less imbricate, 0.2-0.7(-l) mm wide, flat to convex, thinly corticate areoles with sinuate to lobulate margins. Apothecia lecideine to biatorine, 0.2-0.8(-l) mm across, sessile and more or less constricted at base, with a flat to convex, dark reddish brown disc, and a thin, finally excluded proper margin. Proper exciple 48-55 µm wide laterally, the outer part prosoplectenchymatous, reddish brown, of 6-8 µm wide cells, the inner part paler, with up to 13 µm wide cells; epithecium ochraceous brown, 5-12 µm high; hymenium colourless, 45-80 µm high; paraphyses sparingly branched and anastomosing, 1.5-2.5 µm thick at mid-level, the apical cells 3-4(-5) µm wide, with an orange-brown apical cap; hypothecium colourless, 50-70(-75) µm high, with photobiont cells in inner part. Asci 8-spored, clavate, with a thick, K/I + dark blue apical apparatus containing a K/I+ darker blue tubular pore, Mycobilimbia-type. Ascospores 1-celled, hyaline, elongate to subcylindrical or ovoid, (9-)11-15(-17) x 5-6.5(-7.5) µm, with a smooth epispore. Photobiont chlorococcoid, the cells 5-9 µm in diam. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on bark, mainly of conifers, at the base of trunks. The Italian material differs from the description in the paler thallus and in not having biseriate asci. According to Printzen (in litt.) the species is likely to be related to Lecidea berengeriana. It is included in the Italian red list of epiphytic lichens as “Data Deficient” (Nascimbene & al. 2013c).