The monotypic genus Caesiodiscus, typified by C. populicola Holien & Suija was described by Holien & Suija (2021). This bark-inhabiting fungus has a lichen-like macromorphology but an LSU-based phylogeny placed it within Helotiales, with poor support as sister to Pleuroascaceae (Holien & Suija 2021). This family-level relationship within Helotiales is not supported by ITS sequences (P.R. Johnston, unpubl. data) and it should be retained as Helotiales incertae sedis. Caesiodiscus populicola has muriform ascospores, morphologically highly unusual for Leotiomycetes, and the mature asci are 4-spored. Known only from Norway at the time of publication, later reports show the fungus to be more widespread in Europe (A. Suija, pers. comm.) and it has also been found in a native forest in New Zealand (culture ICMP 22561, https://scd.landcareresearch.co.nz/Specimen/ICMP_22561, GenBank ITS and LSU, ON796947 and ON796949) (Holien & Suija 2021).