Lichenicolous species of Hainesia belong to Phacidiales (Leotiomycetes) and are included in an extended concept of Epithamnolia.

The lichenicolous taxa currently included in the genus Hainesia were studied based on the nuclear rDNA (18S, 28S, and internal transcribed spacer [ITS]) genes. The authors found that lichenicolous taxa form a distinct lineage sister to Epiglia gloeocapsae (Phacidiales, Leotiomycetes), only distantly related to the type species of Hainesia (Chaetomellaceae, Helotiales). Owing to morphological similarities, the authors include the lichenicolous species into the previously monotypic genus Epithamnolia. A new species, Epithamnolia rangiferinae, is described, several names are reduced into synonymy, and a key to the species of Epithamnolia is provided. The incorporation of public environmental ITS sequences showed that the closest relatives of these lichenicolous taxa are various endophytic, endolichenic, and soil-inhabiting fungi.