Biology:Tremolecia

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Tremolecia is a small genus of lichen-forming fungi in the family Hymeneliaceae. Its two accepted species form thin crusts on rock and are recognised by their dark, cup-shaped fruiting bodies (apothecia). The better-known species, Tremolecia atrata, is widespread on iron-rich rocks in mountainous and arctic regions.

Taxonomy

The genus was circumscribed by the French lichenologist Maurice Choisy in 1953. Choisy characterized Tremolecia by its [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] (centrally raised) or somewhat [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] (brain-like, with wavy folds) apothecia, rather small spores occurring eight per ascus, and very short, straight [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] (asexual spores produced in flask-shaped structures). He also compared the genus with Gyrothecium.[1]

Description

Tremolecia species are crustose lichens, appearing as a thin crust-like growth on its [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] without a protective outer layer ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]). The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]—the photosynthetic partner in this symbiotic relationship—is a single-celled green alga with nearly spherical to completely spherical cells measuring 7–14 by 6–13 micrometres.[2]

The reproductive structures (ascomata) are cup-shaped fruiting bodies called apothecia. These apothecia are of the [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] type, meaning they have their own distinct margin, and can be either sunken into the lichen surface with a crater-like appearance ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] and more or less [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]) or sitting on top of the surface (sessile). The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]—the tissue forming the rim of the apothecium—appears dark brown and opaque when viewed in cross-section.[2]

Inside the reproductive structures, the paraphyses (sterile filaments) are sparsely branched and occasionally fused ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]), with tips that are not swollen (not [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]). The asci—specialized cells that produce spores—are club-shaped and contain eight spores each. They belong to the Tremolecia-type, characterized by a well-developed [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] (thickened apical region) that stains very weakly with iodine (weakly amyloid), has a thin outer cap that does stain with iodine (external amyloid cap), and lacks a central chamber (ocular chamber).[2]

The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] are [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] (not divided by septa), clear (hyaline), ellipsoid in shape, lack a gelatinous coating (non-[[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]), and have thin walls. The asexual reproductive structures (conidiomata) are flask-shaped pycnidia embedded within the lichen body. The asexual spores (conidia) are rod-shaped ([[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]]).

The genus does not produce any secondary metabolites detectable by standard lichen spot tests.[2]

Species

As of March 2025, Species Fungorum (in the Catalogue of Life), accept two species of Tremolecia:[3]

  • Tremolecia atrata (Ach.) Hertel (1977)
  • Tremolecia dicksonii (J.F.Gmel.) M.Choisy (1953)

Another four species transferred into the genus by Hannes Hertel in 1977 (T. lividonigra, T. nivalis, T. similigena, and T. tuberculans[4]) are not currently accepted by Species Fungorum.

Some species that were at one time placed in this genus have since been transferred to other genera:

  • Tremolecia glauca (Taylor) Hertel & Gotth. Schneid. (1980) is now Paraporpidia glauca[5]
  • Tremolecia jurana (Schaer.) Hertel (1971) is now Farnoldia jurana[6]
  • Tremolecia transitoria (Arnold) Hertel (1977) is now Melanolecia transitoria[7]

References

  1. ↑ Choisy, M. (1953). "Catalogue des lichens de la region lyonnaise. Fasc. 10" (in fr). Bulletin Mensuel de la Société Linnéenne de Lyon 22 (7): 177–192. doi:10.3406/linly.1953.7585. 
  2. ↑ 2.0 2.1 2.2 2.3 Kantvilas, G. (2024). "Tremolecia, version 2024:1". in de Salas, M.F.. Flora of Tasmania Online. Hobart: Tasmanian Herbarium, Tasmanian Museum and Art Gallery. https://flora.tmag.tas.gov.au/lichen-genera/tremolecia/. 
  3. ↑ "Tremolecia". Species 2000: Leiden, the Netherlands. https://www.catalogueoflife.org/data/taxon/CF997. 
  4. ↑ Hertel, H. (1977). Hellmich, Walter. ed (in de). Gesteinsbewohnende Arten der Sammelgattung Lecidea (Lichenes) aus Zentral-, Ost- und Südasien. Khumbu Himal.. 6. Universitätsverlag Wagner Ges. M.B.H.. pp. 145–378 [352]. 
  5. ↑ "Record Details: Tremolecia glauca (Taylor) Hertel & Gotth. Schneid., in Schneider, Biblthca Lichenol. 13: 240 (1980) [1979"]. Index Fungorum. https://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=124697. 
  6. ↑ "Record Details: Tremolecia jurana (Schaer.) Hertel, Khumbu Himal 6(3): 351 (1971)". Index Fungorum. https://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=124697. 
  7. ↑ "Record Details: Tremolecia transitoria (Arnold) Hertel, Khumbu Himal 6(3): 356 (1977)". Index Fungorum. https://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=343788. 

Wikidata ☰ Q10701868 entry



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