The Agaricomycetes are a
class
Class or The Class may refer to:
Common uses not otherwise categorized
* Class (biology), a taxonomic rank
* Class (knowledge representation), a collection of individuals or objects
* Class (philosophy), an analytical concept used differently ...
of
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...
in the division
Basidiomycota
Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Bas ...
. The
taxon
In biology, a taxon ( back-formation from '' taxonomy''; plural 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 n ...
is roughly identical to that defined for the Homobasidiomycetes (alternatively called holobasidiomycetes) by Hibbett & Thorn,
[ with the inclusion of Auriculariales and Sebacinales. It includes not only ]mushroom
A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans.
The standard for the name "mushroom" is ...
-forming fungi, but also most species placed in the deprecated taxa Gasteromycetes and Homobasidiomycetes.[ Within the subdivision Agaricomycotina, which already excludes the smut and ]rust
Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO( ...
fungi, the Agaricomycetes can be further defined by the exclusion of the classes Tremellomycetes
The Tremellomycetes are a class of dimorphic fungi in the Agaricomycotina. Some species have gelatinous basidiocarps (fruiting bodies) or (microscopically) a sacculate parenthesome. There are six orders, 17 families, and 39 genera in the Tremell ...
and Dacrymycetes, which are generally considered to be jelly fungi. However, a few former "jelly fungi", such as ''Auricularia
''Auricularia'' is a genus of fungi in the family Auriculariaceae. Basidiocarps (fruit bodies) are typically gelatinous and ear-shaped, with a slightly downy to conspicuously hirsute upper surface and an under surface that is smooth, wrinkled o ...
'', are classified in the Agaricomycetes. According to a 2008 estimate, Agaricomycetes include 17 orders
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
, 100 families, 1147 genera, and about 21000 species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
.[ Modern molecular phylogenetic analyses have been since used to help define several new orders in the Agaricomycetes: ]Amylocorticiales
Amylocorticiales is an order of fungi in the class Agaricomycetes. The order was circumscribed in 2010 to contain mostly resupinate (crust-like) forms that have been referred to genera '' Anomoporia'', '' Amyloathelia'', '' Amylocorticiellum'', ' ...
, Jaapiales
''Jaapia'' is a genus in the monotypic family Jaapiaceae and order Jaapiales. The genus was first described by Italian mycologist Giacomo Bresadola in 1911, and contains two widely distributed species, '' J. argillacea'' and '' J. ochr ...
,
Classification
Although morphology of the mushroom or fruit body (basidiocarp) was the basis of early classification of the Agaricomycetes,[ this is no longer the case. As an example, the distinction between the '' Gasteromycetes'' (including puffballs) and ''Agaricomycetes'' (most other agaric mushrooms) is no longer recognized as a natural one—various puffball species have apparently evolved independently from agaricomycete fungi. However, most mushroom guide books still group the puffballs or gasteroid forms separate from other mushrooms because the older Friesian classification is still convenient for categorizing fruit body forms. Similarly, modern classifications divide the gasteroid order Lycoperdales between Agaricales and Phallales.
]
Features
All members of the class produce basidiocarps which range in size from tiny cups a few millimeters across to a giant polypore ('' Phellinus ellipsoideus'') greater than several meters across and weigh up to .[ The group also includes what are arguably the largest and oldest individual organisms on earth: the ]mycelium
Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates ...
of one individual '' Armillaria gallica'' has been estimated to extend over with a mass of and an age of 1,500 years.[
]
Ecology
Nearly all species are terrestrial (a few are aquatic), occurring in a wide range of environments where most function as decayers, especially of wood. However, some species are pathogenic or parasitic, and yet others are symbiotic
Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or para ...
(i.e., mutualistic), these including the important ectomycorrhizal
An ectomycorrhiza (from Greek ἐκτός ', "outside", μύκης ', "fungus", and ῥίζα ', "root"; pl. ectomycorrhizas or ectomycorrhizae, abbreviated EcM) is a form of symbiotic relationship that occurs between a fungal symbiont, or my ...
symbionts of forest trees. General discussions on the forms and life cycles of these fungi are developed in the article on mushroom
A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans.
The standard for the name "mushroom" is ...
s, in the treatments of the various orders
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
(links in table at right), and in individual species accounts.
Evolution
A study of 5,284 species with a backbone phylogeny based on 104 genomes[Varga T, Krizsán K, Földi C, Dima B, Sánchez-García M, Sánchez-Ramírez S, Szöllősi GJ, Szarkándi JG, Papp V, Albert L, Andreopoulos W, Angelini C, Antonín V, Barry KW, Bougher NL, Buchanan P, Buyck B, Bense V, Catcheside P, Chovatia M, Cooper J, Dämon W, Desjardin D, Finy P, Geml J, Haridas S, Hughes K, Justo A, Karasiński D, Kautmanova I, Kiss B, Kocsubé S6, Kotiranta H, LaButti KM, Lechner BE, Liimatainen K, Lipzen A, Lukács Z, Mihaltcheva S, Morgado LN, Niskanen T, Noordeloos ME, Ohm RA, Ortiz-Santana B, Ovrebo C, Rácz N, Riley R, Savchenko A, Shiryaev A, Soop K, Spirin V, Szebenyi C, Tomšovský M, Tulloss RE, Uehling J, Grigoriev IV, Vágvölgyi C, Papp T, Martin FM, Miettinen O, Hibbett DS, Nagy LG (2019) Megaphylogeny resolves global patterns of mushroom evolution. Nat Ecol Evol ] has suggested the following dates of evolution:
Agaricomycetidae ~ (–)
Cantharellales (–)
Agaricales (-)
Hymenochaetales
The Hymenochaetales are an order of fungi in the class Agaricomycetes. The order in its current sense is based on molecular research and not on any unifying morphological characteristics. According to one 2008 estimate, the Hymenochaetales con ...
(–)
Boletales
The Boletales are an order of Agaricomycetes containing over 1300 species with a diverse array of fruiting body types. The boletes are the best known members of this group, and until recently, the Boletales were thought to only contain boletes. T ...
(–)
Fossil record
The fruit bodies of Agaricomycetes are extremely rare in the fossil record, and the class does not yet pre-date the Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145& ...
(146–100 Ma).