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Placopyrenium

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Placopyrenium
Placopyrenium bucekii
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Eurotiomycetes
Order: Verrucariales
Family: Verrucariaceae
Genus: Placopyrenium
Breuss (1987)
Type species
Placopyrenium bucekii
(Nádv. & Servít) Breuss (1987)

Placopyrenium is a genus of saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae.[1]

Taxonomy

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The genus was circumscribed in 1987 by the Austrian lichenologist Othmar Breuss. He assigned Placopyrenium bucekii as the type species.[2]

Description

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The genus Placopyrenium is characterised by its epilithic (growing on rocks) thallus, which is thick and distinctly patterned, breaking into areoles (small, island-like sections) or squarrose-areolate (with scale-like, spreading areoles). These areoles have a unique shape, being noticeably narrowed at their base and extending into elongated stipes (stalks), which are ashen in colour on the upper surface due to a protective epinecral layer, while the underside is black. The thallus lacks rhizohyphae (root-like hyphae) and the stipes are directly attached to the substrate.[2]

The entire thallus is composed of cells that are either angular or rounded, measuring 5–10 μm in diameter, forming a structure that is nearly paraplectenchymatous, meaning the cells are closely packed together. The areolae's base and sides are enveloped in a carbonaceous (blackened) cortical layer, providing durability and protection.[2]

In terms of reproductive structures, Placopyrenium develops perithecia (fruiting bodies) within the thallus. These perithecia lack an involucrellum (an outer layer or envelope). The asci (spore-producing structures) within the perithecia are clavate, meaning they are shaped like a club. The spores produced in these asci are arranged in two rows (biseriate), and are either ellipsoidal or ovoid-oblong in shape. These spores are colourless and typically simple, although they are often uniseptate, meaning they have a single internal division (septum). Additionally, the genus produces short, rod-shaped conidia (asexual spores).[2]

Species

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References

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  1. ^ Wijayawardene, Nalin; Hyde, Kevin; Al-Ani, Laith Khalil Tawfeeq; Somayeh, Dolatabadi; Stadler, Marc; Haelewaters, Danny; et al. (2020). "Outline of Fungi and fungus-like taxa". Mycosphere. 11: 1060–1456. doi:10.5943/mycosphere/11/1/8. hdl:10481/61998.
  2. ^ a b c d Nimis, P.L.; Poelt, J. (1987). "The lichens and lichenicolous fungi of Sardinia (Italy)". Studia Geobotanica. 7 (S1): 182–183.
  3. ^ Breuss, O.; Haji Moniri, M. (2017). "A new Placopyrenium species (Ascomycota: Verrucariaceae) from Iran". Herzogia. 30 (1): 177–181.
  4. ^ Roux, C.; Gueidan, C. (2011). "Deux espèces nouvelles de Verrucariaceae des Pyrénées-Orientales (France): Placocarpus melanophthalmosus sp. nov. et Placopyrenium breussii sp. nov". Bulletin de la Société Linnéenne de Provence (in French). 14 (S): 163–176.
  5. ^ Menard, T.; Roux, C. (1995). "Placopyrenium bucekii and notes on Verrucariaceae (Verrucariales, Lichenes)". Mycotaxon. 53: 129–159.
  6. ^ Aptroot, André; Yazici, Kenan (2012). "A new Placopyrenium (Verrucariaceae) from Turkey". The Lichenologist. 44 (6): 739–741. doi:10.1017/S0024282912000382.
  7. ^ a b Orange, Alan (2009). "Two parasitic species of Placopyrenium (Verrucariaceae) from freshwater habitats in north-west Europe". The Lichenologist. 41 (2): 131–139. doi:10.1017/S002428290900841X.
  8. ^ a b c Breuss, O. (2009). "A synopsis of the lichen genus Placopyrenium (Verrucariaceae), with descriptions of new taxa and a key to all species". In Aptroot, André; Seaward, Mark R.D.; Sparrius, Laurens B. (eds.). Biodiversity and ecology of lichens. Liber Amicorum Harrie Sipman. Bibliotheca Lichenologica. Vol. 99. Stuttgart/Berlin: J. Cramer. pp. 93–112. ISBN 978-3-443-58078-0.
  9. ^ Breuss, Othmar (2000). "New taxa of pyrenocarpous lichens from the Sonoran Region". The Bryologist. 103 (4): 705–709. doi:10.1639/0007-2745(2000)103[0705:NTOPLF]2.0.CO;2.