Phylum: Ascomycota Family: Xylariaceae
Annulohypoxylon multiforme (Fr.) Y.M. Ju, J.D. Rogers & H.M. Hsieh
Birch Woodwart
The small fruitbodies grow gregariously, merging into a single unit. Found predominantly on the bark of dead birch. Relatively common with a wide distribution
References:
Ellis & Ellis (1997) Microfungi on Land Plants
Breitenbach & Kranzlin (1984) Fungi of Switzerland, Volume 1, Ascomycetes