Description: Thallus crustose, endosubstratic and poorly evident or (rarely) thinly episubstratic and indistinctly areolate, whitish grey, without a distinct prothallus. Medullary hyphae I+ blue-violet. Apothecia lecideine, black, sessile, rounded or irregular in outline due to mutual compression, 0.2-0.8(-1.3) mm across, with a mostly flat, rough disc, and a thick, raised, persistent proper margin. Proper exciple brown-black with a violet tinge in outer part, paler within, the cortical part 25-45 µm wide laterally, C-, I+ violet; epithecium green-black, irregularly thick, coarsely granulose; hymenium pale brown to pinkish brown, 40-70 µm high, the reddish violet tinge intensifying in K; paraphyses coherent; hypothecium thin, pale violet brown, the hyphal walls with a pale purplish-brown pigment which recats K+ intensifying purplish. Asci 8-spored, narrowly clavate, thick-walled, with a K/I+ pale blue tholus and a strongly amyloid, thin apical cushion, surrounded by a I+ blue outer layer, Lecidea-type. Ascospores 1-celled, hyaline, broadly ellipsoid, 8.5-11(-13) x 4.8-5.6 µm, 1.5-2.2 times as long as wide. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: thallus without lichen substances.
Note: an arctic-alpine silicicolous species of wind-exposed, snow-free sites, most frequent on crystalline schists near or above treeline. The world distribution was mapped by Hertel (2006).