Pseudoparmelia Cyphellata

''Pseudoparmelia'' is a genus of lichen-forming fungi in the family Parmeliaceae. The genus has a pantropical distribution.

Taxonomy

It was circumscribed by Bernt Arne Lynge in 1914, who distinguished the genus from '' Parmelia'' by the presence of pseudocyphellae on the underside of the lichen thallus. However, this distinguishing characteristic was later shown to be an artifact caused by torn rhizines.

The genus was not widely accepted until it was redefined by Mason Hale in the 1970s to include lichens with a pored and narrow, non-ciliate lobes. Further research revealed that this broader definition included a heterogeneous group of species, leading to a more restricted circumscription with most species being transferred to other genera.

Molecular phylogenetics studies have shown that ''Pseudoparmelia'' forms a distinct lineage within the Parmeliaceae, closely related to the genera '' Relicina'' and ''Relicinopsis''. These three genera share features including a pored , isolichenan as cell wall polysaccharide, and relatively small . The genus has its centres of distribution in the Neotropics and southern Africa.

Description

The main body (thallus) of ''Pseudoparmelia'' has a yellowish tint in both its outer layer (upper ) and inner tissue (medulla), caused by the presence of chemicals called secalonic acids. The upper surface has microscopic pores in its protective outer layer, known as a pored . The of the thallus are narrow and lack hair-like projections called .

On the thallus underside, ''Pseudoparmelia'' species have a pale surface with simple root-like structures (rhizines) that attach the lichen to its . The fungal component of these lichens contains isolichenan in its cell walls, a type of polysaccharide that helps give the lichen structure. The cortex contains small amounts of the compound atranorin, while the medulla contains β-orcinol depsidones.

When reproducing, these lichens produce small, ellipsoid to nearly spherical . They also produce another type of reproductive cell called conidia, which are elongated and can be either (tapering at both ends) or thread-like in shape.

''Pseudoparmelia'' species are found primarily in two regions of the world: tropical and subtropical America (the Neotropics) and southern Africa. They can be distinguished from similar-looking genera by their unique combination of chemical compounds, particularly the presence of secalonic acids and absence of usnic acid, as well as their lack of specialised structures like bulbate cilia that are found in related genera. A unique chemical feature of the genus is the presence of terphenyl derivatives called butlerins, compounds that are uncommon in lichen-forming fungi but more frequently found in non-lichenised mushrooms and other basidiomycetes.

Species

*'' Pseudoparmelia arida''
*'' Pseudoparmelia brakoana''
*'' Pseudoparmelia buckiana''
*'' Pseudoparmelia callichroa''
*'' Pseudoparmelia caribaea''
*'' Pseudoparmelia chapadensis''
*'' Pseudoparmelia chlorea''
*'' Pseudoparmelia concomitans''
*'' Pseudoparmelia convexa''
*'' Pseudoparmelia cubensis''
*'' Pseudoparmelia cyphellata''
*'' Pseudoparmelia dahlii''
*'' Pseudoparmelia floridensis''
*'' Pseudoparmelia harrisiana''
*'' Pseudoparmelia hypomiltha''
*'' Pseudoparmelia kalbiana''
*'' Pseudoparmelia regnellii''
*'' Pseudoparmelia relicinoides''
*'' Pseudoparmelia sphaerospora''
*'' Pseudoparmelia uleana''

References

{{Taxonbar, from=Q7255233

Parmeliaceae
Lichen genera
Lecanorales genera
Taxa named by Bernt Arne Lynge
Taxa described in 1914