Lich. de France, 5: 984, 1913. Basionym: Lecanora subfusca var. lecideoides Nyl. Lich. Envir. Paris: 57 - 1896.
Synonyms: Lecanora rubrofusca var. nigra B. de Lesd.; Lecanora sbarbaroana H. Magn. ex Sbarbaro
Distribution: N - Lig.
Description: Thallus crustose, poorly evident or inapparent, rarely whitish and coarsely granulose, poorly delimited. Apothecia 0.1-0.3 mm across, usually numerous, with a brown-black to black, epruinose disc, a well-developed, concolorous proper margin, and a whitish, thin, soon excluded thalline margin. Epithecium brown, without crystals, N-; hymenium and hypothecium colourless. Asci 8-spored, clavate, very thin-walled, with a K/I+ blue, tall tholus penetrated by a faintly amyloid apical cushion, the wall K/I-, surrounded by a blue outer layer, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, (9-)12-16.5 x (4-)6-9.5 μm. Photobiont chlorococcoid. Spot tests: thallus K+ yellow; apothecial margin K+ yellow, C-, KC-, P-, P+ yellowish or P+ reddish. Chemistry: poorly known, atranorin certainly present.
Note: a very poorly known species of siliceous rocks, reported from a few localities in western and southern Europe. Ecological indicator values are tentative.