Description: Thallus crustose, endosubstratic or rarely thinly episubstratic, often poorly evident, whitish to pale grey. Medullary hyphae I+ violet-blue. Apothecia lecideine, black, isolated or crowded, sessile and constricted at base, 1-2.5 mm across, rounded or angular, with a flat to convex disc and a usually persistent, sometimes finally excluded proper margin. Proper exciple dark grey-brown in outer part, paler within, K-, C+ red; epithecium blue-green to green-black, N+ purple-red; hymenium colourless, 50-60 µm high, I+ blue; paraphyses mostly simple, 1.5-2.5 µm thick at mid-level, the apical cells 3.5-4 µm wide; hypothecium dark to pale brown. 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, ellipsoid, 8.5-12 x 3.2-4.2 µm. Photobiont chlorococcoid. Spot tests: thallus K-, C- KC-, P-. Chemistry: thallus with perlatolic acid, apothecia with anziaic acid.
Note: on low siliceous boulders, pebbles and flat stones scattered over the ground in Alpine heaths, sometimes also on large rock faces. The world distribution was mapped by Hertel (2006).