''Tremolecia'' is a small

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

-forming

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

in the family

Hymeneliaceae Hymeneliaceae is a family of lichen-forming fungi in the order Baeomycetales. It contains three genera and about 40 species. The family was circumscribed by German lichenologist Gustav Wilhelm Körber in 1855. Lichens in the Hymeneliaceae ar ...

Taxonomy

The genus was

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

by the French lichenologist Maurice Choisy in 1953.

Description

''Tremolecia'' species are

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...

s, appearing as a thin crust-like growth on its without a protective outer layer (). The —the

photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...

partner in this symbiotic relationship—is a single-celled

green alga The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ( ...

with nearly spherical to completely spherical cells measuring 7–14 by 6–13

micrometre The micrometre (English in the Commonwealth of Nations, Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a uni ...

s. The reproductive structures (

ascomata An ascocarp, or ascoma (: ascomata), is the fruiting body (sporocarp (fungi), sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded ascus, asci, each of which typically contains four to ...

) are cup-shaped fruiting bodies called

apothecia An ascocarp, or ascoma (: ascomata), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. As ...

. These apothecia are of the type, meaning they have their own distinct margin, and can be either sunken into the lichen surface with a crater-like appearance ( and more or less ) or sitting on top of the surface (sessile). The —the tissue forming the rim of the apothecium—appears dark brown and opaque when viewed in cross-section. Inside the reproductive structures, the

paraphyses Paraphyses are erect sterile filament-like support structures occurring among the reproductive apparatuses of fungi, ferns, bryophytes and some thallophytes. The singular form of the word is paraphysis. In certain fungi, they are part of the f ...

(sterile filaments) are sparsely branched and occasionally fused (), with tips that are not swollen (not ). 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 (thickened apical region) that

stains A stain is an unwanted localized discoloration, often in fabrics or textiles. Stain(s) or The Stain(s) may also refer to: Color * Stain (heraldry), a non-standard tincture * Staining, in biology, a technique used to highlight contrast in samples ...

very weakly with

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

(weakly

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of typically 7–13 nm in diameter, a β-sheet secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the human ...

), has a thin outer cap that does stain with iodine (external amyloid cap), and lacks a central chamber (ocular chamber). The are (not divided by septa), clear (

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

ellipsoid An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathemat ...

in shape, lack a gelatinous coating (non-), and have thin walls. The asexual reproductive structures (

conidiomata Conidiomata (singular: Conidioma) are blister-like fruiting structures produced by a specific type of fungus called a coelomycete. They are formed as a means of dispersing asexual spores call conidia, which they accomplish by creating the blister- ...

) are flask-shaped

pycnidia A pycnidium (plural pycnidia) is an asexual fruiting body produced by mitosporic fungi, for instance in the order Sphaeropsidales ( Deuteromycota, Coelomycetes) or order Pleosporales (Ascomycota, Dothideomycetes). It is often spherical or inve ...

embedded within the lichen body. The asexual spores (

conidia A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also ...

) are rod-shaped (). The genus does not produce any

secondary metabolite Secondary metabolites, also called ''specialised metabolites'', ''secondary products'', or ''natural products'', are organic compounds produced by any lifeform, e.g. bacteria, archaea, fungi, animals, or plants, which are not directly involved ...

s detectable by standard lichen spot tests.

Species

Species Fungorum ''Index Fungorum'' is an international project to index all formal names (Binomial nomenclature, scientific names) in the fungus Kingdom (biology), kingdom. As of 2015, the project is based at the Royal Botanic Gardens, Kew, one of three partn ...

(in the

Catalogue of Life The Catalogue of Life (CoL) is an online database that provides an index of known species of animals, plants, fungi, and microorganisms. It was created in 2001 as a partnership between the global Species 2000 and the American Integrated Taxono ...

), accept two species of ''Tremolecia'': * '' Tremolecia atrata'' * '' Tremolecia dicksonii'' Another four species transferred into the genus by

Hannes Hertel Hannes Hertel is a German lichenologist and taxonomist and was Director of the State Herbarium in Munich, Germany 1992–2004. His specialist areas are the fungi and lichens. Early life and education Hannes Hertel was born in 1939. His doctorat ...

in 1977 (''T. lividonigra'', ''T. nivalis'', ''T. similigena'', and ''T. tuberculans'') 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'' is now ''

Paraporpidia glauca ''Paraporpidia'' is a genus of lichen-forming fungi in the family Lecideaceae. It has three species of saxicolous (rock-dwelling) crustose lichens. The genus was circumscribed by Gerhard Rambold and M. Pietschmann in 1989, with ''Paraporpidia ab ...

'' *''Tremolecia jurana'' is now '' Farnoldia jurana'' *''Tremolecia transitoria'' is now '' Melanolecia transitoria''

References

{{Taxonbar, from=Q10701868 Lecanoromycetes Baeomycetales genera Lichen genera Taxa described in 1953 Taxa named by Maurice Choisy