Athallia is a genus of lichen-forming fungi in the family Teloschistaceae.[1] It was circumscribed in 2013 by Ulf Arup, Patrik Frödén, and Ulrik Søchting,[1] and the type species is Athallia holocarpa.[2] The genus name means "without a thallus".
Most species in Athallia have a poorly developed thallus, with the exception of A. scopularis. In A. scopularis, the thallus is well-developed and, meaning it has a lobed structure. The, which is the outer layer of the thallus, is typically an amorphous layer or made up of indistinctly organized tissue (indistinctly), a tissue structure previously referred to as "alveolate" by Vondrák et al. in 2009. In A. scopularis, however, the cortex consists of hyphae (fungal filaments) that are arranged, meaning they run perpendicular to the surface.
Athallia vitellinula is atypical in the genus for having a conspicuous thallus, but it is usually very thin. The apothecia (fruiting bodies) in Athallia are mainly, which means they lack a . The spores produced are, meaning they are divided into two components separated by a central septum with a perforation. Pycnidia, which are small, flask-shaped structures producing asexual spores (conidia), are typically orange in Athallia, but they are often absent. The conidia, when present, are ellipsoid in shape.
All Athallia lichens have a suite of secondary metabolites (lichen products) corresponding to the A as previously elaborated by Søchting.
, Species Fungorum (in the Catalogue of Life) accept 11 species of Athallia: