Description: Thallus crustose, episubstratic, continuous or rimose-areolate in central parts, yellowish white, whitish grey or greenish white, smooth, epruinose. Apothecia lecanorine, sessile, 0.5-1(-1.5) mm across, with a flesh-coloured to pinkish brown, but heavily white-pruinose, flat to rarely slightly convex disc, and a thin, persistent (sometimes finally excluded), entire or flexuose, smooth thalline margin. Thalline exciple ecorticate, with numerous small crystals soluble in K; epithecium brown, with a fine epipsamma, the pigment and the crystals dissolving in K; hymenium colourless, 55-85 µm high; paraphyses branched and anastomosing, not or only slightly thickened at apex; hypothecium colourless, not inspersed with oil droplets. 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, (7-)10-13(-16) x (5-)6-8(-9) µm, the wall <1 µm thick. Photobiont chlorococcoid. Spot tests: thallus and apothecial margin K+ yellow, C-, KC-, P+ orange to red, UV+ pale orange; apothecial disc P+ orange-red. Chemistry: atranorin, chloroatranorin, protocetraric acid.
Note: a mainly temperate, perhaps holarctic lichen found on smooth bark, especially of Fagus, but also of Abies in woodlands; apparently more frequent in the past, but perhaps formerly confused with L. subcarpinea.