| Agaricales | |
|---|---|
 | |
| Agaricus campestris (field mushroom) (Agaricaceae) | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Agaricomycetes |
| Subclass: | Agaricomycetidae |
| Order: | Agaricales Underw. (1899)[2] |
| Subdivisions | |
| Synonyms[3] | |
AmanitalesJülich (1981) | |
TheAgaricales are anorder offungi in thedivisionBasidiomycota. As originally conceived, the order contained all theagarics (gilled mushrooms), but subsequent research has shown that not all agarics are closely related and some belong in other orders, such as theRussulales andBoletales. Conversely, DNA research has also shown that many non-agarics, including some of theclavarioid fungi (clubs and corals) andgasteroid fungi (puffballs and false truffles) belong within the Agaricales. The order has 46extantfamilies, more than 400genera, and over 25,000 describedspecies,[4] along with sixextinct genera known only from the fossil record.[5][6][1] Species in the Agaricales range from the familiarAgaricus bisporus (cultivated mushroom) and the deadlyAmanita virosa (destroying angel) to the coral-likeClavaria zollingeri (violet coral) and bracket-likeFistulina hepatica (beefsteak fungus).
In his three volumes ofSystema Mycologicum published between 1821 and 1832,Elias Fries put almost all of the fleshy, gill-forming mushrooms in the genusAgaricus. He organized the large genus into "tribes", the names of many of which still exist as common genera of today. Fries later elevated several of these tribes to generic level, but later authors—includingGillet,Karsten,Kummer,Quélet, and Staude—made most of the changes. Fries based his classification on macroscopic characters of the fruit bodies and color of the spore print. His system had been widely used as it had the advantage that many genera could be readily identified based on characters observable in the field. Fries's classification was later challenged when microscopic studies ofbasidiocarp structure, initiated byFayod andPatouillard, demonstrated several of Fries's groupings were unnatural.[7] In the twentieth century,Rolf Singer's influential workThe Agaricales in Modern Taxonomy, published in four editions spanning from 1951 to 1986, used both Fries's macroscopic characters and Fayod's microscopic characters to reorganizefamilies and genera; his final classification included 230 genera within 18 families.[8] Singer treated three major groups within the Agaricalessensu lato: the Agaricalessensu stricto,Boletineae, andRussulales. These groups are still accepted by modern treatments based on DNA analysis, as the euagarics clade, bolete clade, and russuloid clade.[9]
Molecular phylogenetics research has demonstrated that the euagarics clade is roughly equivalent to Singer's Agaricalessensu stricto.[10][11][12] A large-scale study by Brandon Matheny and colleagues usednucleic acid sequences representing sixgene regions from 238 species in 146 genera to explore the phylogenetic grouping within the Agaricales. The analysis showed that most of the species tested could be grouped into sixclades that were named the Agaricoid, Tricholomatoid, Marasmioid, Pluteoid, Hygrophoroid and Plicaturopsidoid clades.[13]
Molecular studies have shown that agarics are more divergent than once thought. Agarics in the generaRussula andLactarius, for example, belong to the orderRussulales, whilst agarics in the generaPaxillus andHygrophoropsis belong in theBoletales. Conversely some genera with non-agaric fruit bodies, such as thepuffballs,bird's nest fungi, and manyclavarioid fungi, belong in the Agaricales.
Members of the Agaricales are ubiquitous, with species found in all continents. The great majority are terrestrial, in almost every habitat from woodland and grassland to deserts and dunes. Agaricoid species were long thought to be solely terrestrial, until the 2005 discovery ofPsathyrella aquatica, the only gilled mushroom known to fruit underwater.[14] Species are variouslysaprotrophic orectomycorrhizal, occasionallyparasitic on plants or other fungi, and sometimeslichenized.
the Agaricales include sixmonotypic fossil genera mostly found fossilized inamber. The oldest records are from threeCretaceous age genera; the lateAptianGondwanagaricites magnificus from theCrato Formation (Brazil),[1] theAlbian age (approximately 100Ma)Palaeoagaracites antiquus fromBurmese amber and the slightly youngerTuronianNew Jersey Amber speciesArchaeomarasmius leggeti.[5] The three other species,Aureofungus yaniguaensis,Coprinites dominicana andProtomycena electra are known from single specimens found in theDominican amber mines ofHispaniola.[6]
There are several genera classified in the Agaricales that are i) poorly known, ii) have not been subjected to DNA analysis, or iii) if analysed phylogenetically do not group with as yet named or identified families, and have not been assigned to a specific family (i.e.,incertae sedis with respect to familial placement). These include:[15]
