''Schaereria porpidioides'' is a species of saxicolous (rock-dwelling), crustose lichen in the family

Schaereriaceae ''Schaereria'' is a genus of lichen-forming fungi. It is the sole genus in the family Schaereriaceae, which itself is the only family in the Schaereriales, an order in the subclass Ostropomycetidae of the class Lecanoromycetes. Taxonomy The gen ...

. It is found in the Falkland Islands.

Taxonomy

The species was formally described as a new to science in 2001 by lichenologists Alan Fryday and Ralph Common. It is only known from several

collections Collection or Collections may refer to: * Cash collection, the function of an accounts receivable department * Collection (church), money donated by the congregation during a church service * Collection agency, agency to collect cash * Collection ...

made by Henry Imshaug and Richard Harris in 1968. The type collection was made from Mount Adam at an altitude between , where it was found growing on exposed

siliceous rock Siliceous rocks are sedimentary rocks that have silica (SiO2) as the principal constituent. The most common siliceous rock is chert; other types include diatomite. They commonly form from silica-secreting organisms such as radiolarians, diatoms, or ...

s located in feldmark on a summit ridge. Associated lichens include '' Neuropogon fasciata'', '' Pertusaria spegazzinii'', '' Poeltidea perusta'', and '' Rhizocarpon geographicum''. '' Rimularia andreaeicola'' was later identified as another common associate. The species epithet ''porpidioides'' alludes to the taxon's physical appearance, resembling a species from the genus ''

Porpidia ''Porpidia'' is a genus of crustose lichens in the family Lecideaceae. Taxonomy ''Porpidia'' was circumscribed by the German lichenologist Gustav Wilhelm Körber in 1855, with ''Porpidia trullisata'' designated as the type species. Species , ...

'', such as '' P. macrocarpa'' (the authors note, however, that no direct systematic affiliation with that genus is implied).

Description

The thallus is typically spread out and embedded, becoming noticeable between coarse sandstone grains as a creamy-white layer lacking a well-defined . Occasionally, under microscopic observation, a few brown- pigmented cortical cells are discernible. The thallus generally spans substantial areas, up to in diameter. The thallus's internal structure, or medulla, shows a colour change to blue or red-purple when treated with

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...

- potassium iodide (IKI). Accompanying the thallus are photobionts, green microalgae with cell sizes ranging from 9 to 18

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

in diameter. The apothecia, or spore-bearing structures, are scattered, black or dark brown, and have a constricted base. They measure between 0.8 and 2.0 mm in diameter, and as they mature, they tend to become irregularly shaped. When wet, their can appear brown, and around them, a black protective layer can be observed. Other detailed microscopic features include the

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some ...

, which is clear and stands between 120 and 135 μm tall,

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

that are cylindrical in shape, and that are broadly elliptical. The base structure, or , consists of randomly oriented strands and transitions into a dark-brown layer. This complex structure is interspersed with large crystal groups, clearly visible under specialized lighting. Additionally, , structures producing asexual spores, are black, not frequently found but usually present, and the themselves are cylindrical in shape.

References

{{Taxonbar, from=Q10663136 Lecanoromycetes Lichen species Lichens described in 2001 Taxa named by Alan Fryday Lichens of the subantarctic islands