''Fulgidea'' 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 ...

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

Umbilicariaceae The Umbilicariaceae are a family of lichenized fungi in the Ascomycota. Species of this family are known from a variety of climates, including temperate, boreal, austral, and warmer montane Montane ecosystems are found on the slopes of moun ...

. It has two species of

squamulose lichen A squamulose lichen is a lichen that is composed of small, often overlapping "scales" called . If they are raised from the substrate and appear leafy, the lichen may appear to be a foliose lichen, but the underside does not have a "skin" (cortex), ...

s that grow on bark and on wood.

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 ...

in 2013 by the Norwegian lichenologists Mika Bendiksby and Einar Timdal. They assigned '' Fulgidea oligospora'' 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 ...

. The genus name ''Fulgidea'' is derived from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

word , meaning "lightning", alluding to its preference for growing on burnt wood. The name also reflects its morphological similarities to species within the genus ''

Lecidea ''Lecidea'' is a genus of crustose lichen, crustose lichens with a carbon-black ring or outer margin (exciple) around the fruiting body disc (apothecium), usually (or always) found growing on (Saxicolous lichen, saxicolous) or in (Endolithic lich ...

''. Both species of ''Fulgidea'' had previously been classified in the genus '' Hypocenomyce''.

Description

Genus ''Fulgidea'' is characterized by its

squamulose A squamulose lichen is a lichen that is composed of small, often overlapping "scales" called . If they are raised from the substrate and appear leafy, the lichen may appear to be a foliose lichen, but the underside does not have a "skin" (cortex) ...

thallus, which is closely attached or slightly raised and oriented against gravity. 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 ...

ranges in color from greyish-green to dark brown and can have either a dull or shiny appearance. It lacks a coating (a fine powdery surface layer that sometimes appears frosted) and does not have a , which is an underlying layer of

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 that can sometimes be visible at the lichen's periphery. The

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 ...

(fruiting bodies) of ''Fulgidea'' are black, flat, and maintain a distinct margin. They lack a pruinose covering. The , which is the tissue surrounding the apothecium, is made up of tightly bonded, relatively thin-walled hyphae 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 ...

to shortly cylindrical in shape. The inner parts and rim of the exciple are blackish brown, and the pigment partially dissolves 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 (K) resulting in a brown coloration, but does not react to nitrogen tests (N−). The —the uppermost layer of cells in the apothecium—is brown and contains amorphous substances that also dissolve to release a brown effusion when treated with K. The

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 ...

(spore-bearing structure) is narrowly rhombic with an

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 ...

cap at the tip. The amyloid reaction is a

staining Staining is a technique used to enhance contrast in samples, generally at the Microscope, microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissue (biology), tissues), in cytology (microscopic ...

reaction used to identify certain chemical properties of lichen tissues. The cap includes a small, amyloid —a structure within the ascus tip—with a non-amyloid central plug.

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 ...

, which are asexual reproductive structures, have brown walls. The (asexual spores), are rod-shaped, measuring 7–10

μm The micrometre (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 unit of length in the International System ...

in length and about 1 μm in width. Chemically, ''Fulgidea'' species contain alectorialic and

thamnolic acid Thamnolic acid is a β-orcinol depside with the molecular formula C19H16O11. Thamnolic acid was first isolated from the lichen '' Thamnolia vermicularis'', but it also occur in ''Cladonia ''Cladonia'' is a genus of moss-like lichenized fungi ...

s, which are

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 (

lichen product Lichen products, also known as lichen substances, are organic compounds produced by a lichen. Specifically, they are secondary metabolites. Lichen products are represented in several different chemical classes, including terpenoids, orcinol deri ...

s) specific to certain lichens and contribute to their biochemical characteristics.

Comparison to similar genera

The genus ''Fulgidea'' is primarily distinguished from '' Hypocenomyce'' by its exciple structure. In ''Hypocenomyce'', the exciple is colorless internally and green at the rim (K−, N+ violet), and is only partially with hyphae separated by

lecanoric acid Lecanoric acid is a chemical produced by several species of lichen.ubChem - Lecanoric acid"> Lecanoric acid is classified as a polyphenol and a didepside, and it functions as an antioxidant. It is an ester of orsellinic acid with itself. The acid ...

crystals (C+ red). Additionally, ''Hypocenomyce'' features a green epihymenium and pycnidium wall that react positively to violet staining with N and contains lecanoric acid, unlike ''Fulgidea'' which lacks amorphous substances. The pycnoconidia in ''Hypocenomyce'' are generally longer, ranging from to in shape. Contrasting with '' Pycnora'', ''Fulgidea'' has an ascus that is narrowly rhombic with an amyloid cap and a small amyloid tholus with a non-amyloid central plug, whereas ''Pycnora'' has a broadly (club-shaped) ascus without an amyloid cap but with a well-developed, amyloid tholus and a deeper amyloid area along the wall. Additionally, ''Pycnora'' has a strictly crustose thallus and a green epihymenium that turns violet with N and dissolves in K, with shorter pycnoconidia that are more or less spherical to shortly bacilliform. '' Elixia'', another genus, differs from ''Fulgidea'' as it forms a crustose or thallus, with star-shaped to apothecia, paraphyses with a distinct pigment zone at the top of the apical cell, and lacks secondary compounds. '' Xylopsora'', another genus in the

, is morphologically, anatomically and ecologically similar to ''Fulgidea'' and differs mainly in secondary chemistry: it contains friesiic acid rather than alectorialic and thamnolic acids.

Species

* '' Fulgidea oligospora'' –

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

, USA;

Sakha Republic Sakha, officially the Republic of Sakha (Yakutia), is a republics of Russia, republic of Russia, and the largest federal subject of Russia by area. It is located in the Russian Far East, along the Arctic Ocean, with a population of one million ...

, Russia * '' Fulgidea sierrae'' –

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, USA

References

{{Taxonbar, from=Q38816080 Umbilicariales Umbilicariales genera Taxa described in 2013 Lichen genera Taxa named by Einar Timdal