Leptorhaphis epidermidis (Ach.) Th. Fr.

    Thallus absent though orange spots of Trentepohlia (or spots of green algae) may sometimes be seen on bark surface. Perithecia scarce, scattered, immersed at first then prominent, rounded or ovoid, black, sometimes surrounded with a brown-blackish halo of mycelium towards the base, ostiole counter-relief, conspicuous, 0.2-0.5 mm diam. Ascospores elongate fusiform, apices pointed, falcate (more precisely boomerang-shaped), 1-septate, 25-35 x 2-3.5 µm. 'Pycnidia' sometimes numerous, visible as tiny little black dots. Chemical spot tests negative. Very common on bark of birch trees (Betula), most often non-lichenized but sometimes associated to Trentepohlia. Not to be confused with Arthopyrenia analepta which is very similar and also foound on birch trees. See also Arthopyrenia punctiformis and Arthonia punctiformis.*