Agaricales

The Agaricales are an order of fungi in the division Basidiomycota. As originally conceived, the order contained all the agarics (gilled mushrooms), but subsequent research has shown that not all agarics are closely related and some belong in other orders, such as the Russulales and Boletales. Conversely, DNA research has also shown that many non-agarics, including some of the clavarioid fungi (clubs and corals) and gasteroid fungi (puffballs and false truffles) belong within the Agaricales. The order has 46 extant families, more than 400 genera, and over 25,000 described species, along with six extinct genera known only from the fossil record. Species in the Agaricales range from the familiar Agaricus bisporus (cultivated mushroom) and the deadly Amanita virosa (destroying angel) to the coral-like Clavaria zollingeri (violet coral) and bracket-like Fistulina hepatica (beefsteak fungus).

History, classification and phylogeny

In his three volumes of Systema Mycologicum published between 1821 and 1832, Elias Fries put almost all of the fleshy, gill-forming mushrooms in the genus Agaricus. 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—including Gillet, 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.