Description: Thallus crustose, endosubstratic or thinly episubstratic, continuous to rimose, pale grey or greenish grey. Medullary hyphae I-. Apothecia biatorine, rounded to slightly irregular in outline, rarely tuberculate, adnate to sessile and constricted at base, 0.25-0.7(-1) mm across, with a ochre to reddish brown (in older apothecia sometimes almost black), flat to slightly convex disc, and a concolorous or usually slightly darker, soon excluded proper margin. Proper exciple pale brown in outer part, colourless or with small pigmented droplets within, 25-60 µm wide laterally, of radiating hyphae with swollen end cells; epithecium reddish brown, 5-10 µm high , K-; hymenium colourless to pale yellowish brown, 35-70 µm high, I+ blue; paraphyses simple or sparingly branched and anastomosing, 0.7-2 µm thick at mid-level, the apical cells 2.5-5 µm wide, with a brown cap; hypothecium colourless or very pale brown. Asci 8-spored, distinctly thickened at the apex, with a I+ blue tholus, the outer gelatinous coat I+ pale blue, approaching the Bacidia-type. Ascospores 1-celled, hyaline, fusiform, (7-)9-16(-18) x 3-4.5(-5) µm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a mainly boreal-montane, probably circumpolar species of acid bark, especially of conifers, in humid-cold situations, e.g. in Sphagnum bogs, which apparently reaches Sicilia along the Apennines (Sicilian records, however, need re-confirmation). Closely related to L. rhododendri and certainly not a Lecidea s.str.