Dendrographa decolorans (Turner & Borrer ex Sm.) Ertz & Tehler = Schismatomma decolorans (Turner & Borrer ex Sm.) Clauzade & Vezda

    Thallus crustose, thin crust forming, more or less cracked, pale grey, grey-greenish, pale grey-brown, dull brownish, often with characteristic violet or lilac tinge (but disappearing in herbarium), covered with farinose soralia, concolourous or sligtly paler, grey-mauve very rarely ochraceous, often very numerous and possibly giving a leprose aspect to the thallus, darker inconspicuous hypothallus. Apothecia very rare, elongated or circular, irregular in shape, 0.8-1.3 mm diam., pruinose. Ascospores elongate, curve, 1-septate, 30-37 x 4-5 µm. Photobiont: Trentepohlia (characterized by orange scars). C-, K-, KC-, Pd-. On bark of deciduous trees and notably Quercus, in more or less dry habitat (avoid humidity), very rare on rocks.