The genus Ertzia was established by Brendan P. Hodkinson and Robert Lücking in 2014, with E. akagerae as its type, and only, species.

[4] The genus name honours the lichenologist Damien Ertz for his important contributions to the understanding of lichenized fungi evolution and classification.

[4] A distinctive feature of the genus is its cortex, which is formed by a layer of colourless (hyaline) cells that resemble pieces of a jigsaw puzzle.

[4] This cortical structure distinguishes it from Lepidostroma sensu stricto and is somewhat similar to features found in some unrelated lichen genera such as Cora and Dictyonema, though these belong to a different order (Agaricales).

[4] While superficially similar to the Botrydina-type thallus found in genera such as Multiclavula, Semiomphalina, and some Lichenomphalia species, Ertzia can be distinguished by its larger granules and distinctive jigsaw puzzle-shaped rather than isodiametric-angular cortical cells.