''Trapelia'' is a
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 ...
of
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
Trapeliaceae.
These lichens form tight,
crusty patches on rocks and bark that may appear smooth at first but often crack into small plates over time. The genus was established by the French lichenologist
Maurice Choisy in 1929 and contains more than 20 species found worldwide. Most species reproduce through small, -shaped
fruiting bodies
The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...
that range from pale pink-brown to nearly black, and many can be identified by specific
chemical compounds
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
they produce.
Taxonomy
''Trapelia'' 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 1929. He assigned ''
Trapelia coarctata'' as the
type species
In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
.
Description
''Trapelia'' forms a low-profile
crust that adheres tightly to its
substrate
Substrate may refer to:
Physical layers
*Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached
** Substrate (aquatic environment), the earthy material that exi ...
.
Colonies
A colony is a territory subject to a form of foreign rule, which rules the territory and its indigenous peoples separated from the foreign rulers, the colonizer, and their '' metropole'' (or "mother country"). This separated rule was often or ...
may begin as a thin, continuous film with a smooth outer edge; over time this film either cracks into a mosaic of tiny plates () or arises directly as discrete areoles that later press together to form an almost seamless crust. The uppermost layer of fungal tissue () is only weakly differentiated and comprises rounded cells, while a delicate film of dead cell remnants often leaves a fine frost-like sheen (). A narrow, sometimes inconspicuous —an initial growth of colourless
hypha
A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.
Structure
A hypha consists of one o ...
e—may fringe the colony. The internal algal partner is a minute, spherical
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 ( ...
( photobiont).
Reproductive structures appear as rounded
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 ...
that sit flush with, or slightly raised above, the
thallus
Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entir ...
surface. When young they are partly embedded; mature apothecia may display a thin, brown, often ragged margin formed from disrupted thallus tissue, giving the impression of a "pseudothalline" rim. The ranges from pale pink-brown to almost black and is frequently uneven or roughened. Internally, the is brown and may dissolve to an orange-brown solution in
potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash.
Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...
solution (a common diagnostic test), whereas the underlying is pale to light brown. Slender
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 ...
thread the
hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in oth ...
; these filaments branch and fuse profusely near their tips, but their ends remain narrow rather than swollen.
Each
ascus
An ascus (; : asci) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some gen ...
is slightly club-shaped,
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
...
weakly blue in
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 ...
and carries eight single-celled, colourless
ascospore
In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse Division (botany), division of fungi. After two parental cell nucleus, nuclei fuse, the ascu ...
s that are
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 ...
al and 9–25
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 (μm) long. In many species tiny, immersed
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 ...
generate asexual
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 ...
—straight or slightly curved rods—that help the lichen spread. Chemical analyses detect one or more of three common
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—
gyrophoric acid
Gyrophoric acid is a tridepside. It is a double ester of the orsellinic acid. It can also be found in most of the species of the lichen genera '' Actinogyra'', '' Lasallia'', and '' Umbilicaria'' .
Natural occurrence and biosynthesis
Gyropho ...
,
lecanoric acid and 5-''O''-methylhiascic acid—which can assist with species-level identification.
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 18 species of ''Trapeila''.
*''
Trapelia antarctica''
*''
Trapelia atrocarpa''
*''
Trapelia calvariana''
*''
Trapelia coarctata''
*''
Trapelia collaris''
*''
Trapelia concentrica''
*''
Trapelia coreana''
*''
Trapelia corticola''
*''
Trapelia crystallifera''
*''
Trapelia elacista''
*''
Trapelia glebulosa''
*''
Trapelia herteliana''
*''
Trapelia involuta''
*''
Trapelia lilacea''
*''
Trapelia macrospora''
*''
Trapelia obtegens''
*''
Trapelia placodioides''
*''
Trapelia rubra''
*''
Trapelia sitiens''
*''
Trapelia stipitata''
*''
Trapelia thieleana''
*''
Trapelia tristis''
References
{{Taxonbar , from1=Q3580507 , from2=Q5281574
Baeomycetales
Lichen genera
Baeomycetales genera
Taxa described in 1929
Taxa named by Maurice Choisy