Lecanora allophana (Ach.) Nyl.
Thallus crustose, rather thick, smooth to rugose and sometimes verrucose and areolate, pale grey, pale grey-greenish, dull whitish, prothallus absent. Apothecia usually very numerous, more or less distorted owing to the compression, sessile, 1-2 mm diam., disc flat to slightly concave, more or less glossy, dark brown-red, brown-chocolate, chestnut-brown, exciple thick, markedly crenulate and wavy, sometimes hanging over the disc, epihymenium not granulose and without crystals. Ascospores simple, colourless, 14-19 x 8-10 µm. Photobiont: Trebouxia. Thallus: C-, K+ yellow, Pd-. Rare in our prospection area (under decline?), on bark of isolated deciduous tress, notably ornmental trees in alignments or in parks and gardens, notably Fagus.*