The genus was proposed in 2020 based on molecular and morphological studies of a lichen previously classified in the genera Psoroma and Pannaria.

Phormopsora is characterised by its large, scale-like structures called squamules that form pale grey rosettes, and by the presence of unique lichen substances not found in other members of its family.

The species is primarily found in southern South America, particularly in Chile, where it grows on the trunks of evergreen Nothofagus trees in humid, temperate rainforests.

Both the genus Phormopsora and its species were described as new to science in 2020 by the lichenologists Arve Elvebakk, Soon Gyu Hong, and Chae Haeng Park.

[3] Phormopsora isabellina was originally described as Psoroma isabellinum by Edvard August Vainio in 1899, based on a specimen collected in Chile.

The thallus is often surrounded by a distinct prothallus, which is a thin layer of fungal hyphae extending beyond the main body of the lichen.

The upper cortex, or outer layer, of the squamules is paraplectenchymatous, consisting of fungal cells with thick walls arranged in a tissue-like manner.

[3] Phormopsora isabellina is primarily found in southern South America, with its main distribution in Chile and a single reported occurrence in Argentina.