A taxonomic and biogeographic overview of the genus Myrionora is provided. Two species are recognized, M. albidula (Willey) R. C. Harris and M. pseudocyphellariae (Etayo) S. Ekman & Palice comb. nov. The genus is characterized by polysporous asci, the presence of crystals in the hymenium and proper exciple that partly consist of lobaric acid, and a photobiont with large cells (mostly in the range 12–20 µm). Myrionora albidula is currently known from Germany, Norway, Sweden, the Russian Federation (Altayskiy Kray, Chelyabinskaya Oblast', Khabarovskiy Kray and Zabaykal'skiy Kray), and the United States (Alaska, Connecticut, Maine and Massachusetts). It inhabits bark of deciduous trees and shrubs and conifers over a wide range of latitudes. Myrionora pseudocyphellariae is known from Chile and Ecuador, where it has been encountered on lichens and decaying bark. Based on morphological characteristics, we conclude that Myrionora belongs in the Ramalinaceae.

The new species Lecanora lasalliae Pérez-Ortega & Etayo is described from Spain. It is included provisionally in Lecanora s. lat as characters such as Lecanora-type ascus, exciple composed of thick radiating hyphae and the usual presence of algal cells in the excipulum or its lichenicolous habitus on Lasallia pustulata, do not fit well within any known genus of lichenicolous or lichenized fungi. Its taxonomic affinities with several taxa are discussed, including the parasitic Lecanora gyrophorina.