The genus Thelocarpon (incl. Ahlesia) includes with all transitions species with open to closed ascocarps. The probable change of the function of the ascocarps seems to be connected with a series of reductions of the apical apparatus from well developed over poorly developed and present for a short time to completely deficient. According to the used criterion (form of the ascocarp, paraphyses, form of the ascus, apical apparatus) a subdividing of the genus would bring different results and seems therefore unnatural. Thelocarpon lichenicola (FUCK.) POELT et HAFELLNER is a new combination.