The taxonomic position of the genus Heydenia (Pyronemataceae, Pezizales) based on molecular and morphological data

Molecular and morphological data indicate that the genus Heydenia is closely related to the cleistothecial ascomycete Orbicula (Pyronemataceae, Pezizales). Observations on the disposition and the immediate surroundings of immature spores within the spore capsule suggest that the Heydenia fruiting bodies are teleomorphs producing early evanescent asci in stipitate cleistothecia. The once advocated identity of Heydenia with Onygena is refuted on molecular grounds. Onygena arietina E. Fischer is transferred to Heydenia.