Arthonia vinosa Leight.
Arthonia lurida f. vinosa (Leight.) Zahlbr.
Thallus crustose, thin, effuse, thinly powdery to scurfy-granular, whitish, cream-ochre, pale pink-ochre, often with stained pale orange-brown, orange zones (notably around apothecia). Apothecia irregular, approximately rounded, 0,3-0,6 mm, convex to bulging, not pruinose, orange-red-brown to brown-black. Ascospores ovoid-ellipsoid to clavate (one cell bigger than the other), uni-septate, colourless but old ascospores brown and warted, 11-15 x 4-5 µm. Pycnidia frequent. Photobiont : Trentepohlia. Thallus C-, K± pale purple notably on apothecia and orange spots. On bark or lignum of old trees, especially Quercus in old woodlands and ancient parklands. Not to be confused with Arthonia spadicea deprived of orange zones and with dark-brown apothecia and smaller ascospores and with Arthonia didyma, previously mixed up but with flat and smaller apothecia.*