''Agyrium'' 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 saprophytic

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

Agyriaceae The Agyriaceae are a family of lichenized fungi in the order Pertusariales. It contains two genera: '' Agyrium'', and '' Miltidea''. The family was circumscribed by August Carl Joseph Corda in 1838. In 2018, using a molecular phylogenetic Mol ...

. It probably evolved from a

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 ...

ancestor, as it is closely related to many lichenized species of fungi.Esslinger, T. L. 2009. A cumulative checklist for the lichen-forming, lichenicolous and allied fungi of the continental United States and Canada. North Dakota State University. First posted December 1 1997; most recent update 27 August, 2009. Fargo, North Dakota.
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Taxonomy

''Agyrium'' was first proposed by

Elias Magnus Fries Elias Magnus Fries (15 August 1794 – 8 February 1878) was a Swedish mycologist and botanist. He is sometimes called the Mycology, "Linnaeus of Mycology". In his works he described and assigned botanical names to hundreds of fungus and li ...

in his 1821 work ''

Systema Mycologicum Systema Mycologicum is a systematic classification of fungi drawn up in 1821 by the Swedish mycologist and botanist Elias Fries Elias Magnus Fries (15 August 1794 – 8 February 1878) was a Swedish mycologist and botanist. He is some ...

'', although the name was not published validly as a

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 ...

was not indicated; Fries published the name validly a year later in the second volume of the same work. The species '' Agyrium rufum'' was assigned as the type by

Frederic Clements Frederic Edward Clements (September 16, 1874 – July 26, 1945) was an American plant ecologist and pioneer in the study of both plant ecology and vegetation succession. Biography Born in Lincoln, Nebraska, he studied botany at the University o ...

and

Cornelius Lott Shear Cornelius Lott Shear (March 26, 1865 February 2, 1956) was an American mycology, mycologist and plant pathologist who served as a senior pathologist at the USDA Bureau of Plant Industry. Born in Coeyman's Hollow, Albany County, New York, on Mar ...

in 1931.

Description

Characteristics of genus ''Agyrium'' include the following: a poorly developed

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 ...

that is immersed in 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 ...

; ascomata in the form of an

apothecium 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. Ascoc ...

with a reduced ring-shaped exciple (the layer surrounding 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 ...

that sometimes develops into a distinct margin);

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 ...

that are highly branched; and

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 ...

and thin-walled. The

mycelia Mycelium (: mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Its normal form is that of branched, slender, entangled, anastomosing, hyaline threads. Fungal colonies composed of mycelium are fo ...

of ''Agyrium'' fungi, although not strictly lichenised, are associated with and sometimes penetrate

green algae 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 ...

– particularly near the apothecia. This is a condition that has been described as "facultative parasitism".

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 ...

accepts two species of ''Agyrium''. *''

Agyrium aurantium ''Agyrium'' is a genus of saprophytic fungi in the family Agyriaceae. It probably evolved from a lichen ancestor, as it is closely related to many lichenized species of fungi. Taxonomy ''Agyrium'' was first proposed by Elias Magnus Fries in hi ...

'' *'' Agyrium rufum'' The type species, ''Agyrium rufum'', has a largely

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

distribution and occurs widely in Europe, although it has also been recorded in

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

. ''Agyrium aurantium'' occurs in China. Although 46

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

have been placed in ''Agyrium'' since its inception, many of them were described more than a century ago and have not been investigated with modern

molecular A molecule is a group of two or more atoms that are held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, ...

techniques. Several of them have since been transferred to other genera. For example: *''Agyrium caesium'' = ''

Puttea caesia ''Puttea'' is a genus of lichen-forming fungi with uncertain familial placement in the order Lecanorales. The genus comprises four species. Finnish lichenologists Soili Stenroos and Seppo Huhtinen established the genus ''Puttea'' in 2009 for th ...

'' *''Agyrium densum'' = '' Mellitiosporiella densa'' *''Agyrium flavescens'' = '' Skyttella mulleri'' *''Agyrium nigricans'' = '' Platygloea nigricans'' *''Agyrium nitidum'' = '' Agyriella nitida'' *''Agyrium phragmiticola'' = '' Neottiosporina phragmiticola'' *''Agyrium solidaginis'' = '' Ploettnera solidaginis'' *''Agyrium vulpinum'' = '' Phacopsis vulpina''

References

{{Taxonbar, from=Q4694793 Pertusariales Pertusariales genera Taxa described in 1822 Taxa named by Elias Magnus Fries