Description: Thallus crustose, poorly developed and mostly endosubstratic, sometimes thinly episubstratic and of scattered, whitish grey areoles. Medullary hyphae I-. Apothecia lecideine, black, (0.2-)0.4-0.8(-1.3) mm across, not or only slightly constricted at base, often clustered, with a strongly convex disc and a very thin, soon excluded proper margin. Proper exciple poorly developed, very thin, greenish black to blue-black in outer part, more or less colourless within; epithecium olive-green to greenish black; hymenium colourless to brownish or reddish, 30-60 µm high, not well delimited from the hypothecium; paraphyses richly branched and anastomosing, with a thick gelatinous sheath, the apical cell to 6 µm wide, with a dark cap; hypothecium reddish brown to purplish red, K+ bright purple. 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 to indistinctly 1-septate, hyaline, narrowly ellipsoid to almost dumbbell-shaped, 7-10(-12) x (2-)2.5-3.5 µm. Conidia bacilliform, 6-8 µm long. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: thallus without lichen substances.
Note: an arctic-alpine species of humid siliceous rocks near and above treeline; probably more widespread in the Alps. It does not belong to Lecidea s.str.