Cryptoschizotrema
{{Short description|Genus of lichen-forming fungi}}
{{Use British English|date=November 2023}}
{{Automatic taxobox
| image =
| taxon = Cryptoschizotrema
| authority = Aptroot, Lücking & M.Cáceres (2019)
| type_species = Cryptoschizotrema cryptotrema
| type_species_authority = (Nyl.) Aptroot, Lücking & M.Cáceres (2019)
| subdivision_ranks =
| subdivision = C. cryptotrema
}}
Cryptoschizotrema is a genus of lichen-forming fungi in the family Graphidaceae. It has two species. The genus was circumscribed in 2019 by lichenologists André Aptroot, Robert Lücking, and Marcela Cáceres. The genus name alludes to the similarity in anatomy with Schizotrema species. This resemblance is due to the partially {{lichengloss|carbonized}}, concentrically layered, and fissured {{lichengloss|excipulum}}, which gives the impression that the Schizotrema-like excipulum is concealed beneath a protective layer. The type species was originally described by William Nylander in 1867, as a species of Thelotrema.
Description
The ascomata of Cryptoschizotrema lichens are immersed-{{lichengloss|erumpent}} and rounded, with the {{lichengloss|disc}} concealed beneath a narrow pore. The {{lichengloss|proper margin}} is hidden by a whitish thalline layer, and when abraded, it reveals brown to black fissured {{lichengloss|lobules}} that form concentric layers in older specimens. Notably, a {{lichengloss|columella}} is absent in this genus. The {{lichengloss|excipulum}} of Cryptoschizotrema is {{lichengloss|prosoplectenchymatous}}, displaying a dark brown colour that may partially {{lichengloss|carbonize}} towards its apex. As the ascomata mature, the excipulum develops distinct layers or striations. {{lichengloss|Periphysoids}}, however, are not present.
The hymenium of this lichen is transparent, featuring unbranched {{lichengloss|paraphyses}}. {{lichengloss|Ascospores}} are typically found in quantities of one to two, though occasionally up to four per ascus. These ascospores are {{lichengloss|muriform}}, measuring up to 100 by 30 μm, and have an oblong to ellipsoid shape. The {{lichengloss|distoseptate|distoseptae}}, with relatively thin walls and septa, along with angular {{lichengloss|lumina}}, contribute to the ascospores' colourless appearance. Additionally, they are I-negative, indicating their non-amyloid nature. The secondary chemistry of the genus is characterized by the presence of psoromic acid, which causes the thallus to display a P+ (yellow) reaction with standard chemical spot tests.
Species
Species in this genus occur in Central and South America.
- Cryptoschizotrema cryptotrema {{au|(Nyl.) Aptroot, Lücking & M.Cáceres 2019)}}
- Cryptoschizotrema minus {{au|E.L.Lima & Lücking (2019)}}
References
{{Reflist|refs=
{{Catalogue of Life |id=62P6F |title=Cryptoschizotrema |access-date=15 March 2023}}
}}
{{Taxonbar|from=Q117186618}}
Category:Taxa described in 2019
Category:Taxa named by André Aptroot