Lecanora albella (Pers.) Ach.
Lecanora pallida (Schreber) Rabenh.
Thallus crustose, thin, smooth to minutely granulose, sometimes slightly crazed or areolate towards the center, whitish, grey-whitish, sometimes with a white prothallus. Apothecia usually abundant, scattered all over the thallus, sessile, 0.5-1 mpm diam., disc flat, pinkish, pale brown-yellowish, pale brown-pinkish, appearing white due to dense white pruine, exciple determinate, powdery, more or less wavy, persistent, whitish. Ascopores simple, colourless, broadly ellipsoid, 10-14 x 6-9 µm. Photobiont: Trebouxia. Thallus: C-, K+ yellow, Pd+/- yellow-orange; apothecia: C-, K-, Pd+ bright yellow to red but most often orange. Common, on smooth bark of trees and notably Fagus, scarce on smooth sections of Quercus barks. Not to be confused with Lecanora carpinea of which apothecia are C+ yellow and Pd- and to Lecanora intumescens equally K+ with apothecia exciple Pd+ orange, but apothecia of the latter are much less powdery and less whitish.*