| Tremolecia | |
|---|---|
 | |
| Tremolecia atrata (brown red), Nassbodensee ~ 2000 m elevation, Austria | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Baeomycetales |
| Family: | Hymeneliaceae |
| Genus: | Tremolecia M.Choisy (1953) |
| Type species | |
| Tremolecia dicksonii (J.F.Gmel.) M.Choisy (1953) | |
| Species | |
Tremolecia is a small genus of lichen-forming fungi in the family Hymeneliaceae.
The genus was circumscribed by the French lichenologist Maurice Choisy in 1953. [1]
Tremolecia species are crustose lichens, appearing as a thin crust-like growth on its substrate without a protective outer layer ( ecorticate ). The 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. [2]
The reproductive structures (ascomata) are cup-shaped fruiting bodies called apothecia. These apothecia are of the lecideine type, meaning they have their own distinct margin, and can be either sunken into the lichen surface with a crater-like appearance ( immersed and more or less aspicilioid ) or sitting on top of the surface (sessile). The proper exciple —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 ( anastomosed ), with tips that are not swollen (not 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 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). [2]
The ascospores are simple (not divided by septa), clear (hyaline), ellipsoid in shape, lack a gelatinous coating (non- 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 ( bacilliform ).
The genus does not produce any secondary metabolites detectable by standard lichen spot tests. [2]
As of March 2025 [update] , Species Fungorum (in the Catalogue of Life), accept two species of Tremolecia: [3]
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: