Cystobasidiomycetes discovered by Spribille et al. (2016) in the cortex of lichens might play a role in the cortex architecture and may even be responsible for the appearance of foliose and fruticose thalli in the Lecanoromycetes. Other studies discovered also a high diversity of these yeasts, but others found very few lichens colonized by them, suggesting that they are less ubiquitous. In the present study, we tested the presence and distribution of these basidiomycete yeasts in the Arthoniales, using an array of taxa with various thallus types, from corticate and ecorticate crustose thalli to fruticose species. A preliminary study has been carried out on a limited number of samples. DNA was extracted using the CTAB protocol, ITS loci were amplified with UMI primers and sequenced using MinION techniques. The Ligation Sequencing Amplicons Native Barcoding kit was used to build the library. It proved to be an excellent technique as it allowed to obtain a very deep sequencing with high quality sequences. Not only the mycobiont and the photobiont were obtained, but also sequences from other taxa, such as plants, phytopathogenic fungi or Cystobasidiomycetes, although sometimes in small amount. However, the group of Cystobasidiomycetes highlighted by Spribille et al. (2016) were not detected in the Arthoniales, independently from the thallus growth form or the presence of a cortex. Nevertheless, corticate Arthoniales have a different cortex type than foliose and fruticose thalli of the Lecanoromycetes studied by Spribille et al. (2016). In conclusion, Cystobasidiomycetes may well have played a role in the cortex or thallus architecture in Lecanoromycetes, but not in Arthoniales. However, to better support this conclusion a larger number of samples are needed, notably in order to cover more lichenized lineages.