Schizotrema

Schizotrema
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Graphidales
Family: Graphidaceae
Genus: Schizotrema
Mangold & Lumbsch (2009)
Type species
Schizotrema zebrinum
Mangold (2009)
Species

S. flavolucens
S. guadeloupense
S. quercicola
S. schizolomum
S. subzebrinum
S. vezdanum
S. zebrinum

Schizotrema is a genus of lichen-forming fungi in the family Graphidaceae. The genus was circumscribed in 2009 by Armin Mangold and H. Thorsten Lumbsch.[1]

Description

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The genus Schizotrema consists of lichens with a thallus that can range from being immersed in the substrate to appearing more superficial. The thallus is usually pale in colour and often inconspicuous. Its photosynthetic partner, or photobiont, is a green alga from the genus Trentepohlia. The prothallus, a structure that sometimes surrounds the edges of the lichen, is faint and brown, blending subtly with the substrate. Some species produce soralia, which are small, discrete, and punctiform (dot-like) structures that release powdery reproductive propagules for asexual reproduction.[2]

The ascomata, or sexual reproductive structures are generally rounded and embedded within the thallus. These structures are surrounded by a thick, layered thalline rim, which may flake away as the lichen ages. The true exciple, the tissue surrounding the spore-producing region, is dark brown to black and multilayered. It may or may not react with iodine at its base (amyloid or non-amyloid) and is lined with small hair-like structures known as periphysoids.[2]

Internally, the hymenium (spore-producing region) is tightly packed and does not react to iodine staining (non-amyloid). The hamathecium, the network of sterile filaments within the hymenium, is composed of unbranched paraphyses with tips that are not thickened. The asci, which are sac-like structures where spores develop, are clavate (club-shaped) and contain between one and eight spores. These asci also do not react to iodine. The spores produced by Schizotrema are transversely septate (divided by cross-walls) or muriform (divided into multiple compartments by both transverse and longitudinal walls). They are hyaline (colourless) to yellowish, sometimes becoming brown at full maturity, and may have a thin gelatinous coating. Asexual reproductive structures called conidiomata have not been observed to occur in this genus.[2]

Species

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The species once known as Schizotrema cryptotrema (Nyl.) Rivas Plata & Mangold (2010) is now Cryptoschizotrema cryptotrema.[6]

References

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  1. ^ a b c d e Mangold, A.; Elix, J.A.; Lumbsch, H.T. (2009). "Thelotremataceae". Flora of Australia. Vol. 57. Australian Biological Resources Study/CSIRO Publishing. pp. 653–659. ISBN 978-0-643-09664-6.
  2. ^ a b c Aptroot, A.; Weerakoon, G.; Cannon, P.; Coppins, B.; Sanderson, N.; Simkin, J. (2023). Ostropales: Graphidaceae, including the genera Allographa, Clandestinotrema, Crutarndina, Diploschistes, Fissurina, Graphis, Leucodecton, Phaeographis, Schizotrema, Thelotrema and Topeliopsis (PDF). Revisions of British and Irish Lichens. Vol. 36. p. 17.Open access icon
  3. ^ Lücking, Robert; Mangold, Armin; Lumbsch, H. Thorsten (2016). "A worldwide key to species of the genera Myriotrema and Glaucotrema (lichenized Ascomycota: Graphidaceae), with a nomenclatural checklist of species published in Myriotrema". Herzogia. 29 (2): 493–513. doi:10.13158/heia.29.2.2016.493.
  4. ^ Ertz, Damien; Sanderson, Neil; Coppins, Brian J.; Klepsland, Jon T.; Frisch, Andreas (2019). "Opegrapha multipuncta and Schismatomma quercicola (Arthoniomycetes) belong to the Lecanoromycetes". The Lichenologist. 51 (5): 395–405. doi:10.1017/s002428291900029x.
  5. ^ Kantvilas, Gintaras (2020). "Tasmanian chroodiscoid thelotremoid lichens (Graphidaceae) revisited". Phytotaxa. 459 (3): 209–218. doi:10.11646/phytotaxa.459.3.2.
  6. ^ "Record Details: Schizotrema cryptotrema (Nyl.) Rivas Plata & Mangold, in Rivas Plata, Lücking, Sipman, Mangold, Kalb & Lumbsch, Lichenologist 42(2): 184 (2010)". Index Fungorum. Retrieved 30 January 2022.