The Agaricomycetes are a

class Class, Classes, 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 d ...

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 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, Basi ...

. The

taxon 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 ...

is roughly identical to that defined for the Homobasidiomycetes (alternatively called holobasidiomycetes) by Hibbett & Thorn, with the inclusion of

Auriculariales The Auriculariales are an order of fungi in the class Agaricomycetes. Species within the order were formerly referred to the " heterobasidiomycetes" or "jelly fungi", since many have gelatinous basidiocarps (fruit bodies) that produce spores on ...

and

Sebacinales The Sebacinales are an order of fungi in the class Agaricomycetes. Taxa have a widespread distribution and are mostly terrestrial, many forming mycorrhizas with a wide variety of plants, including orchids Orchids are plants that belong to ...

. It includes not only

mushroom A mushroom or toadstool is the fleshy, spore-bearing Sporocarp (fungi), fruiting body of a fungus, typically produced above ground on soil or another food source. ''Toadstool'' generally refers to a poisonous mushroom. The standard for the n ...

-forming fungi, but also most species placed in the deprecated taxa

Gasteromycetes The gasteroid fungi are a group of fungi in the Basidiomycota. Species were formerly placed in the obsolete class Gasteromycetes Fr. (literally "stomach fungi"), or the equally obsolete order Gasteromycetales Rea, because they produce spores insi ...

and Homobasidiomycetes. Within the subdivision

Agaricomycotina Agaricomycotina is one of three subdivisions of the Basidiomycota (fungi bearing spores on basidia), and represents all of the fungi which form macroscopic fruiting bodies. Agaricomycotina contains over 30,000 species, divided into three classe ...

, 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(OH) ...

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 Trem ...

and

Dacrymycetes The Dacrymycetes are a class of fungi in the Basidiomycota. The class currently contains the single order Dacrymycetales, with a second proposed order Unilacrymales now treated at the family level. The order contains four families and has a cosm ...

, which are generally considered to be

jelly fungi Jelly fungi are a paraphyletic group of several heterobasidiomycete fungal orders from different classes of the subphylum Agaricomycotina: Tremellales, Dacrymycetales, Auriculariales and Sebacinales. These fungi are so named because their f ...

. However, a few former "jelly fungi", such as ''

Auricularia ''Auricularia'' is a genus of fungi in the family (biology), 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 s ...

'', are classified in the Agaricomycetes. According to a 2008 estimate, Agaricomycetes include 17

orders Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * H ...

, 100

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

, 1147

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

, and about 21000

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

. Modern

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

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,

Stereopsidales The Stereopsidales are an order of fungi in the class Agaricomycetes. There is a single family, Stereopsidaceae. It was first described in 2014 to contain the genera ''Stereopsis'', which was until then classified in the order Polyporales, and ...

, and Lepidostromatales.

Classification

Although

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

of the mushroom or

fruit body 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 ...

(basidiocarp) was the basis of early

classification Classification is the activity of assigning objects to some pre-existing classes or categories. This is distinct from the task of establishing the classes themselves (for example through cluster analysis). Examples include diagnostic tests, identif ...

of the Agaricomycetes, this is no longer the case. As an example, the distinction between the ''

'' (including

puffball Puffballs are a type of fungus featuring a ball-shaped fruit body that (when mature) bursts on contact or impact, releasing a cloud of dust-like spores into the surrounding area. Puffballs belong to the division Basidiomycota and encompass sever ...

s) and ''Agaricomycetes'' (most other

agaric An agaric () is a type of fungal fruiting body characterized by the presence of a pileus (cap) that is clearly differentiated from the stipe (stalk), with lamellae (gills) on the underside of the pileus. It is a type of mushroom (or toadstool) ...

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 The Lycoperdales are a now outdated order of fungi. The order included some well-known types such as the giant puffball, the earthstars, and other tuberous fungi. They were defined as having epigeous basidiomes, a hymenium present, one to three ...

between

Agaricales The Agaricales are an order (biology), order of fungi in the division (mycology), division Basidiomycota. As originally conceived, the order contained all the agarics (gilled mushrooms), but subsequent research has shown that not all agarics are ...

and

Phallales The Phallales is an order of fungi in the subclass Phallomycetidae. Taxonomy The order contains three families: * Claustulaceae which includes 12 species in 6 genera * Gastrosporiaceae which includes 3 species in a single genus * Phallaceae ...

Features

All members of the class produce

basidiocarp In fungi, a basidiocarp, basidiome, or basidioma () is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do no ...

s which range in size from tiny cups a few millimeters across to a giant

polypore Polypores, also called bracket or shelf fungi, are a morphological group of basidiomycete-like gilled mushrooms and hydnoid fungi that form large fruiting bodies called conks, which are typically woody, circular, shelf- or bracket-shaped, ...

(''

Phellinus ellipsoideus ''Phellinus ellipsoideus'' (formerly ''Fomitiporia ellipsoidea'') is a species of polypore fungus in the family Hymenochaetaceae, a specimen of which produced the largest fungal fruit body ever recorded. Found in China, the fruit bodies produce ...

'') 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 (: 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 one individual '' Armillaria gallica'' has been estimated to extend over with a mass of and an age of 1,500 years. Agaricomycetes also have antibacterial properties. Agaricomycetes can help in research in treating bacteria.

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 In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ...

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

, and yet others are

symbiotic Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...

(i.e., mutualistic), these including the important

ectomycorrhizal An ectomycorrhiza (from Greek ἐκτός ', "outside", μύκης ', "fungus", and ῥίζα ', "root"; ectomycorrhizas or ectomycorrhizae, abbreviated EcM) is a form of symbiotic relationship that occurs between a fungal symbiont, or mycobion ...

symbionts of forest trees. General discussions on the forms and life cycles of these fungi are developed in the article on

s, in the treatments of the various

(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 has suggested the following dates of evolution:

Agaricomycetidae Agaricomycetidae is a subclass of fungi, in the division Basidiomycota. The name Agaricomycetidae had previously been named by Marcel Locquin in 1984, but his publication did not contain a Latin diagnosis and it is therefore invalid under th ...

~ (–)
Cantharellales (–)

(-)

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. ...

(–)

Fossil record

The fruit bodies of Agaricomycetes are extremely rare in the

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

, 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 143.1 ...

(146–100 Ma). The oldest Agaricomycetes fossil, dating from the lower Cretaceous (130–125 Ma) is '' Quatsinoporites''. It is a fragment of a

poroid {{Short pages monitor