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Placopyrenium

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Genus of lichen

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.

Taxonomy

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

Description

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.

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.

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).

Species

References

  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. ^ 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. ^ 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. ^ 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.
Taxon identifiers
Placopyrenium
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