Buellia disciformis

Thallus superficial, thin, greyish, very slightly verrucose.

Asci 8-spored, not reacting with KOH.

Paraphyses filiform, septate, branched at the apex, with swellings in these terminal cells, covered by a heavily pigmented amorphous cap that is responsible for the blackish colour of the ascomata.

Mature ascospores dark brown, ellipsoidal, with a distinct central septum and thick-walled.