Absconditella


Absconditella is a genus of lichen-forming fungi in the family Stictidaceae. These lichens are characterised by their inconspicuous growth and small, cup-shaped fruiting bodies that are often hidden within a jelly-like mass containing green algae. The genus name, meaning "hidden", reflects their elusive nature. Absconditella species are typically found on short-lived surfaces such as decaying wood, mosses, and unstable soil. Genetic studies have revealed that the genus is more complex than previously thought, with some species being moved to a new genus, Absconditonia, and others potentially representing groups of closely related species. Despite their small size and easily overlooked nature, environmental DNA studies suggest that Absconditella lichens may be more widespread than collections indicate.

Taxonomy

The genus was circumscribed in 1965 by Czech lichenologist Antonín Vězda, with Absconditella sphagnorum assigned as the type species. Absconditella is characterised by gyalectoid apothecia with a hymenium that is not amyloid, without a dark pigment and thalli containing green algae as photobionts. The genus name means "hidden", a reference to the scant structure of the thallus and its small apothecia.
Molecular phylogenetics studies have shown that Absconditella is polyphyletic within Stictidaceae. The genus Geisleria has been found to be nested within Absconditella, leading to the transfer of Geisleria sychnogonioides to Absconditella. Additionally, a new genus, Absconditonia, has been circumscribed to accommodate some species previously placed in Absconditella.
The conservation of the name Absconditella against Geisleria has been proposed to maintain nomenclatural stability.

Characteristics

Absconditella species typically have minute, ascomata that are often sunken into a gel-like thallus. The can be either composed of parallel hyphae or cellular. Paraphyses are simple and indistinctly septate, occasionally branched only in the upper part. vary in shape and septation among species.

Habitat and distribution

Species of Absconditella are often found on ephemeral substrates such as decaying wood, bryophytes, and unstable soil. Environmental DNA studies suggest that both Absconditella and Absconditonia may be more widespread than previously thought based on collected specimens alone.

Species

, Species Fungorum accepts 13 species of Absconditella, although more species than this have been proposed for inclusion.
Research suggests that A. sphagnorum may represent a complex of multiple species.