{{Short description|Genus of lichen-forming fungi}} {{Use dmy dates|date=March 2025}} {{Automatic taxobox | image = Tremolecia atrata.jpg | image_caption = ''Tremolecia atrata'' (brown red), Nassbodensee ~ 2000 m elevation, Austria | taxon = Tremolecia | authority = M.Choisy (1953) | type_species = ''Tremolecia dicksonii'' | type_species_authority = (J.F.Gmel.) M.Choisy (1953) | subdivision_ranks = Species | subdivision = ''T. atrata''<br /> ''T. dicksonii'' }}

'''''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 {{lichengloss|umbonate}} (centrally raised) or somewhat {{lichengloss|gyrose}} (brain-like, with wavy folds) apothecia, rather small spores occurring eight per ascus, and very short, straight {{lichengloss|pycnoconidia}} (asexual spores produced in flask-shaped structures). He also compared the genus with ''Gyrothecium''.<ref name="Choisy 1953"/>

==Description==

''Tremolecia'' species are crustose lichens, appearing as a thin crust-like growth on its {{lichengloss|substrate}} without a protective outer layer ({{lichengloss|ecorticate}}). The {{lichengloss|photobiont}}—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.<ref name="Kantvilas 2024"/>

The reproductive structures (ascomata) are cup-shaped fruiting bodies called apothecia. These apothecia are of the {{lichengloss|lecideine}} type, meaning they have their own distinct margin, and can be either sunken into the lichen surface with a crater-like appearance ({{lichengloss|immersed}} and more or less {{lichengloss|aspicilioid}}) or sitting on top of the surface (sessile). The {{lichengloss|proper exciple}}—the tissue forming the rim of the apothecium—appears dark brown and opaque when viewed in cross-section.<ref name="Kantvilas 2024"/>

Inside the reproductive structures, the paraphyses (sterile filaments) are sparsely branched and occasionally fused ({{lichengloss|anastomosed}}), with tips that are not swollen (not {{lichengloss|capitate}}). 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 {{lichengloss|tholus}} (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).<ref name="Kantvilas 2024"/>

The {{lichengloss|ascospores}} are {{lichengloss|simple}} (not divided by septa), clear (hyaline), ellipsoid in shape, lack a gelatinous coating (non-{{lichengloss|halonate}}), 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 ({{lichengloss|bacilliform}}).

The genus does not produce any secondary metabolites detectable by standard lichen spot tests.<ref name="Kantvilas 2024"/>

==Species== {{As of|2025|March}}, Species Fungorum (in the Catalogue of Life), accept two species of ''Tremolecia'':<ref name="CoL"/> * ''Tremolecia atrata'' {{au|(Ach.) Hertel (1977)}} * ''Tremolecia dicksonii'' {{au|(J.F.Gmel.) M.Choisy (1953)}}

Another four species transferred into the genus by Hannes Hertel in 1977 (''T.&nbsp;lividonigra'', ''T.&nbsp;nivalis'', ''T.&nbsp;similigena'', and ''T.&nbsp;tuberculans''<ref name="Hertel 1977"/>) 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'' {{au|(Taylor) Hertel & Gotth. Schneid. (1980)}} is now ''Paraporpidia glauca''<ref name="IF: Tremolecia glauca"/> *''Tremolecia jurana'' {{au|(Schaer.) Hertel (1971)}} is now ''Farnoldia jurana''<ref name="IF: Tremolecia jurana"/> *''Tremolecia transitoria'' {{au|(Arnold) Hertel (1977)}} is now ''Melanolecia transitoria''<ref name="IF: Tremolecia transitoria"/>

==References== <references>

<ref name="Choisy 1953">{{cite journal |last=Choisy |first=M. |year=1953 |title=Catalogue des lichens de la region lyonnaise. Fasc. 10 |trans-title=Catalog of lichens of the Lyon region. Fascicle 10 |journal=Bulletin Mensuel de la Société Linnéenne de Lyon |volume=22 |issue=7 |pages=177–192 |doi=10.3406/linly.1953.7585 |language=fr}}</ref>

<ref name="CoL">{{Catalogue of Life |id= CF997 |title=''Tremolecia'' |access-date=17 March 2025}}</ref>

<ref name="Hertel 1977">{{cite book |last=Hertel |first=H. |year=1977 |title=Gesteinsbewohnende Arten der Sammelgattung ''Lecidea'' (Lichenes) aus Zentral-, Ost- und Südasien |series=Khumbu Himal. |publisher=Universitätsverlag Wagner Ges. M.B.H. |trans-title=Rock-dwelling species of the collective genus ''Lecidea'' (Lichenes) from Central, East, and South Asia |editor-last=Hellmich |editor-first=Walter |volume=6 |pages=145–378 [352] |language=de}}</ref>

<ref name="IF: Tremolecia glauca">{{cite web |title=Record Details: ''Tremolecia glauca'' (Taylor) Hertel & Gotth. Schneid., in Schneider, Biblthca Lichenol. 13: 240 (1980) [1979] |url=https://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=124697 |publisher=Index Fungorum |access-date=17 March 2015}}</ref>

<ref name="IF: Tremolecia jurana">{{cite web |title=Record Details: ''Tremolecia jurana'' (Schaer.) Hertel, Khumbu Himal 6(3): 351 (1971) |url=https://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=124697 |publisher=Index Fungorum |access-date=17 March 2015}}</ref>

<ref name="IF: Tremolecia transitoria">{{cite web |title=Record Details: ''Tremolecia transitoria'' (Arnold) Hertel, Khumbu Himal 6(3): 356 (1977) |url=https://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=343788 |publisher=Index Fungorum |access-date=17 March 2015}}</ref>

<ref name="Kantvilas 2024">{{cite web |last=Kantvilas |first=G. |year=2024 |title=''Tremolecia'', version 2024:1 |editor-first=M.F. |editor-last=de Salas |work=Flora of Tasmania Online |publisher=Tasmanian Herbarium, Tasmanian Museum and Art Gallery |location=Hobart |url=https://flora.tmag.tas.gov.au/lichen-genera/tremolecia/}}</ref>

</references>

{{Taxonbar|from=Q10701868}}

Category:Lecanoromycetes Category:Baeomycetales genera Category:Lichen genera Category:Taxa described in 1953 Category:Taxa named by Maurice Choisy