Arthonia apotheciorum (A. Massal.) Almq.

Parasite lichen of Lecanora dispersa apothecia. 

     Thallus absent. Apothecia developing in the host apothecia, initially as small black round-shaped dots 0,1-0,3 mm in diam., and then increasing in size up to be contiguous blackening the whole host apothecia. Ascospores long, ellipsoid, uni-septate, 9-15 x 3-5 µm. C-, K-, P-. This species grows as parasite of Lecanora dispersa : Lecanora albescens, etc., apothecia.  Aspect more or less similar to Arthonia varians growing on Lecanora rupicola, that has narrower spores.*