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Ochrolechia

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Ochrolechia
Ochrolechia parella
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Pertusariales
Family: Ochrolechiaceae
Genus: Ochrolechia
A.Massal. (1852)[1]
Type species
Ochrolechia tartarea
(L.) Zahlbr. (1852)
Synonyms[2]

Ochrolechia is a genus of crustose lichens in the family Ochrolechiaceae.[3] These lichens typically form uneven, often thick, crust-like growths on various surfaces and are characterised by their white to pale grey thalli, which may have a greenish tint. The genus has a long evolutionary history, with fossils dating back to the Paleogene period, about 34 million years ago. Ochrolechia species have disc-like apothecia (fruiting bodies), which are usually yellowish or brownish-pink and often covered with a fine white powdery coating. The genus is widely distributed and includes both common and rare species, with some found in extreme environments such as arctic and alpine regions. Ochrolechia lichens produce diverse secondary metabolites, including orcinol depsides, depsidones, and xanthones.

Fossil history

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Paleontological studies have revealed that Ochrolechia existed as far back as the Paleogene period, approximately 34 million years ago. This discovery was made through the analysis of well-preserved amber fossils from Europe. These fossils include several Ochrolechia specimens that show morphological similarities to modern species, such as O. subplicans and O. xanthostoma. Two of these ancient Ochrolechia specimens were found hosting lichenicolous fungi of the genus Lichenostigma, indicating a long-standing symbiotic relationship between these fungi and their lichen hosts. The presence of such fossils provides calibration points for understanding the evolutionary timeline of both Ochrolechia and Lichenostigma.[4]

Description

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The genus Ochrolechia comprises crustose lichens that typically form uneven, often thick, crust-like growths. The thallus, or body, of these lichens can vary in appearance from smooth and continuous to slightly cracked (rimose). In some cases, the thallus may appear as scattered, convex warts or, more rarely, as minutely shrubby due to the presence of tiny papillae or spine-like extensions. The colour of the thallus ranges from white or pale grey to dark grey, often with a greenish tint. A prothallus, which is a preliminary growth that may be visible around the edges of the thallus, is sometimes present and grey, though it may also be absent.[5]

The upper surface of the thallus generally lacks a distinct protective layer (cortex), or may have a very thin cortex made up of thin-walled fungal filaments (hyphae). The lichen's symbiotic partner, or photobiont, is a chlorococcoid alga, which contributes to the lichen's overall colour and undertakes photosynthesis.[5]

The reproductive structures of Ochrolechia, the apothecia, are disc-like and typically expanded, though in rare cases, they may be pore-like (poriform). The discs are usually yellowish or brownish-pink in colour, often covered with a fine white powdery coating known as pruina. The apothecia are surrounded by a well-developed thalline margin, which is a rim of tissue derived from the thallus itself. In some species, a narrow true exciple, the tissue surrounding the hymenium (spore-producing layer), is visible.[5]

The hymenium in Ochrolechia apothecia is relatively tall, measuring between 150–200 μm. The hamathecium, which supports the developing spores, consists of thin, densely branched, and interconnected filaments known as paraphyses. The asci, or spore-producing cells, contain between two and eight spores, and have thick, amyloid walls, meaning they stain blue with iodine and are similar to those found in the genus Pertusaria. The ascospores themselves are relatively large, lack internal divisions (aseptate), have relatively thin walls considering their size, and are smooth in texture.[5]

Ochrolechia also reproduces asexually through pycnidia, which are flask-shaped structures embedded in the thallus. The conidia (asexual spores) produced by the pycnidia are cylindrical to elongated and are straight rather than curved.[5]

Chemically, Ochrolechia species are known to produce orcinol depsides and depsidones, particularly gyrophoric and lecanoric acids, as well as xanthones and fatty acids. These compounds contribute to the lichen's characteristics and can be used in chemical spot tests to help identify the species.[5]

Species

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As of August 2024, Species Fungorum (in the Catalogue of Life) accepts 41 species of Ochrolechia.[6]

Ochrolechia szatalaensis
Ochrolechia trochophora
Ochrolechia upsaliensis

References

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  1. ^ Massalongo, A.B. (1852). Ricerche sull'autonomia dei licheni crostosi (in Italian). p. 30.
  2. ^ "Synonymy: Ochrolechia A. Massal., Ric. auton. lich. crost. (Verona): 30 (1852)". Species Fungorum. Retrieved 28 October 2021.
  3. ^ 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:11336/151990.
  4. ^ Kaasalainen, Ulla; Kukwa, Martin; Rikkinen, Jouko; Schmidt, Alexander R. (2019). "Crustose lichens with lichenicolous fungi from Paleogene amber". Scientific Reports. 9 (1): 1–7. Bibcode:2019NatSR...910360K. doi:10.1038/s41598-019-46692-w. PMC 6637111. PMID 31316089.
  5. ^ a b c d e f Cannon, P.; Kukwa, M.; Coppins, B.; Fletcher, A.; Sanderson, N.; Simkin, J. (2021). Pertusariales: Ochrolechiaceae, including the genera Lepra, Ochrolechia and Varicellaria (PDF). Revisions of British and Irish Lichens. Vol. 5. pp. 8–9. Open access icon
  6. ^ Species Fungorum. "Ochrolechia". Catalog of Life. Retrieved 15 April 2021.
  7. ^ a b Kukwa, M. (2009). "Ochrolechia aegaea and O. alaskana, two species with gyrophoric and variolaric acids in the cortex". Graphis Scripta. 21 (2): 42–48.
  8. ^ Vainio, Edvard A. (1926). "Lichenes Africani Novi". Annales Universitatis Fennicae Aboënsis (in Latin). 2 (3): 1–33.
  9. ^ Kantvilas, G.; Fryday, A.M. (2021). "Validation of Henry Imshaug's "Ochrolechia alectoronica" (lichenised Ascomycetes, Pertusariales), with notes on O. weymouthii Jatta and a key to the genus Ochrolechia in Tasmania". Swainsona. 35 (5): 67–72.
  10. ^ a b c d e Ren, Qiang (2017). "A revision of the lichen genus Ochrolechia in China". The Lichenologist. 49 (1): 67–84. doi:10.1017/S0024282916000529.
  11. ^ a b c d e f Brodo, Irwin M. (1991). "Studies in the lichen genus Ochrolechia. 2. Corticolous species of North America". Canadian Journal of Botany. 69 (4): 733–772. doi:10.1139/b91-099.
  12. ^ Kukwa, Martin (2011). The lichen genus 'Ochrolechia' in Europe. Gdansk: Fundacja Rozwoju Uniwersytetu Gdańskiego. ISBN 9788375311709.
  13. ^ a b Spribille, Toby; Fryday, Alan M.; Pérez-Ortega, Sergio; Svensson, Måns; Tønsberg, Tor; Ekman, Stefan; Holien, Håkon; Resl, Philipp; Schneider, Kevin; Stabentheiner, Edith; Thüs, Holger; Vondrák, Jan; Sharman, Lewis (2020). "Lichens and associated fungi from Glacier Bay National Park, Alaska". The Lichenologist. 52 (2): 61–181. doi:10.1017/S0024282920000079. PMC 7398404. PMID 32788812.
  14. ^ Lumbsch, H.T.; Ahti, T.; Altermann, S.; De Paz, G.A.; Aptroot, A.; Arup, U.; et al. (2011). "One hundred new species of lichenized fungi: a signature of undiscovered global diversity" (PDF). Phytotaxa. 18 (1): 9–11. doi:10.11646/phytotaxa.18.1.1.
  15. ^ Ertz, Damien; Fryday, Alan; Schmitt, Imke; Charrier, Maryvonne; Dudek, Magdalena; Kukwa, Martin (2016). "Ochrolechia kerguelensis sp. nov. from the Southern Hemisphere and O. antarctica reinstated from the synonymy of O. parella". Phytotaxa. 280 (2): 129–140. doi:10.11646/phytotaxa.280.2.3.
  16. ^ Elix, J.A. (2007). "Further new crustose lichens (Ascomycota) from Australia". Australasian Lichenology. 61: 21–25.
  17. ^ Lumbsch, H. Thorsten; Messuti, María Inés; Nash, Thomas H. (2003). "Ochrolechia splendens (Pertusariaceae), a new species from south-western North America". The Lichenologist. 35 (5–6): 387–391. Bibcode:2003ThLic..35..387L. doi:10.1016/S0024-2829(03)00057-4.
  18. ^ Magnusson, A.H. (1939). "Western American lichens, mainly from Oregon". Meddelelser från Götebörgs Botaniska Trädgård. 13: 237–253.
  19. ^ Verseghy, K. (1962). Die Gattung Ochrolechia. Beihefte zur Nova Hedwigia (in German). Vol. 1. p. 118.
  20. ^ Jia, Z.F.; Zhao, Z.T. (2005). "A new species of the lichen genus Ochrolechia from China". Mycosystema. 24: 162–163.
  21. ^ Verseghy, K. (1958). "Studien über die Gattung Ochrolechia II. Neue Flechten". Annales Historico-Naturales Musei Nationalis Hungarici (in German). 50: 75–85.
  22. ^ Jatta, A. (1911). "Lichenes lecti in Tasmania a W. Weymouth". Bolletino della Società Botanica Italiana. 1911: 253–260.
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