Phyllopsora is a genus of lichen-forming fungi in the family Ramalinaceae.
The characteristics of a fossilized Phyllopsora, P. dominicana, found in Dominican amber, suggests that the main distinguishing features of the genus have remained unchanged for tens of millions of years.
The genus was circumscribed by the Swiss botanist Johannes Müller Argoviensis in 1894, with Phyllopsora breviuscula assigned as the type species.
In 2019, a proposal was made to conserve the name Phyllopsora against the earlier names Triclinum and Crocynia. This was due to Phyllopsora including species that are the types of these earlier generic names, which would have priority. The proposal argued that conserving Phyllopsora would be the least disruptive option, as taking up Triclinum would require 56 new combinations, while Crocynia included many species now considered to belong to other genera. In 2024, the Nomenclature Committee for Fungi recommended conservation of Phyllopsora against Triclinum and Crocynia, with 80% of the committee voting in favour.
The genus Phyllopsora is distinguished by its scale-like to almost leaf-like (foliose) body (thallus) that often has a distinct border (prothallus). Its reproductive structures, known as asci, have a unique feature: an amyloid dome and a narrow, cone-shaped central structure. The fruiting bodies (apothecia) of this genus are made up of highly gelatinized (jelly-like) fungal threads. These threads show no clear separation between the different structural layers of the apothecium, and this gelatinised texture is consistent throughout the central and marginal areas of the apothecium as well as in the supporting structures . The produced by Phyllopsora are small, with thin walls, and are typically not divided into separate compartments (rarely septate).
, Species Fungorum accepts 48 species of Phyllopsora: