Botany: Fungus. Hongos. Funji: Agaricus - Part 1

Agaricus

 Agaricus xanthoderma

 

 

 

Agaricus is a large and important genus of mushrooms containing both edible and poisonous species, with possibly over 300 members worldwide^[1][2]. The genus includes the common ("button") mushroom (Agaricus bisporus) and the field mushroom (Agaricus campestris), the dominant cultivated mushrooms of the West.

Members of Agaricus are characterized by having a fleshy cap or pileus, from the underside of which grow a number of radiating plates or gills on which are produced the naked spores. They are distinguished from other members of their family, Agaricaceae, by their chocolate-brown spores. Members of Agaricus also have a stem or stipe, which elevates the pileus above the object on which the mushroom grows, and a partial veil, which protects the developing gills and later forms a ring or annulus on the stalk.

Taxonomy

For many years members of the genus Agaricus were given the generic name Psalliota, and this can still be seen in older books on mushrooms. All proposals to conserve Agaricus against Psalliota or vice versa have so far been considered superfluous.^{[citation needed]}

Several origins of Agaricus have been proposed; It possibly derives "from Agarica of Sarmatica, a district of Russia" (!).^{[citation needed]} Note also Greek ἀγαρικ^[3] όν "a sort of tree fungus" (There's been an AgariconPersoonia 1:180) Adans. genus, treated by Donk in

Donk reports Linnaeus' name is devalidated (so that the proper author citation apparently is "L. per Fr., 1821") because Agaricus was not linked to Tournefort's name (Linnaeus places both Agaricus Dill. and Amanita Dill. in synonymy), but truly a replacement for Amanita Dill., which would require that A. quercinus, not A. campestris be the type. This question compounded by the fact that Fries himself used Agaricus roughly in Linnaeus' sense (which leads to issues with Amanita), and that A. campestris was eventually excluded from Agaricus by Karsten and was apparently in Lepiota at the time Donk wrote this, commenting that a type conservation might become necessary.^[4]

The alternate name for the genus, Psalliota, derived from the Greek psalion/ψάλιον, "ring", was first published by Fries (1821) as trib. Psalliota. The type is Agaricus campestris (widely accepted, except by Earle, who proposed A. cretaceus). Paul Kummer (not Quélet, who merely excluded Stropharia) was the first to elevate the tribe to a genus. Psalliota was the tribe containing the type of Agaricus, so when separated, it should have caused the rest of the genus to be renamed, but this did not happen. It seems to be currently not considered valid, or a junior homotypic synonym, anyway the explanation is that it was raised by (in retrospect) erroneously maintaining the tribe name.^[4]

Phylogenetics

The use of phylogenetic analysis to determine evolutionary relationships amongst Agaricus species has increased our understanding of this taxonomically difficult genus, although there remains much work to be done to fully delineate infrageneric relationships. Prior to these analyses, the genus Agaricus, as circumscribed by Rolf Singer (1986), was divided into 42 species grouped into five sections based on reactions of mushroom tissue to air or various chemical reagents, as well as subtle differences in mushroom morphology.^[5]Restriction fragment length polymorphism analysis demonstrated that this classification scheme needed revision.^[6]

Sections

This genus is divided into several sections:

• Section Agaricus
• Section Arvense Konrad & Maubl.

Contains 19 species in six subgroups similar to the horse mushroom, A. arvensis, and with versatile heterothallic life cycles.^[7]

• Section Xanthodermatei

Outlined by Singer in 1948, this section includes species with various characteristics similar to the type species A. xanthodermus.^[8] The section forms a single clade based on analysis of ITS1+2.^[9]  Section Chitonioides   Section Sanguinoletti

• Section Spissicaules (Hainem.) Kerrigan
• Section Duploannulatae 
•  
• Based on DNA analysis of ITS1, ITS2, and 5.8S sequences, the section Duploannulatae (also known as section Hortenses) may be divided into six distinct clades, five of which correspond to well-known species from the temperate Northern Hemisphere: A. bisporus, A. subfloccosus, A. bitorquis, A. vaporarius and A. cupressicola. The sixth clade comprises the species complex A. devoniensis.^[10]    
•  
• Edibility 
  
  
  The genus contains the most widely consumed and best known mushroom today, Agaricus bisporus, with A. campestris also well known. The most notable inedible species is the yellow-staining mushroom A. xanthodermus.^{[citation needed]} All three are found worldwide.
  

One species reported from Africa, A. aurantioviolaceus, is reportedly deadly poisonous.[citati

Con el nombre de champiñón se denomina genéricamente a las especies de hongos del género Agaricus, de las cuales algunas se cultivan como comestibles, en especial Agaricus bisporus, el champiñón de París. 

Características

Las especies de champiñones presentan generalmente fructificaciones carnosas, mayoritariamente de tamaño medio a grande; el sombrero es hemisférico inicialmente, después convexo y finalmente más o menos aplanado o ligeramente deprimido, de color blanquecino o parduzco. El pie es cilíndrico y tanto regular como engrosado o atenuado hacia la base; siempre porta un anillo, más o menos desarrollado, que puede ser persistente o caduco y se separa con facilidad de la carne del sombrero.

Las láminas (himenóforo) son libres, es decir no están fijadas al pie, densas, de color muy pálido al comienzo (blanquecino, grisáceo o rosáceo) después con matices rosados, sean fuertes o débiles, y finalmente de color marrón-negruzco. La carne suele ser densa y firme, de color blanquecino pero en contacto con el aire adquiere tonalidades rojizas o amarillentas, en ocasiones ligeras y en otras bastante intensas.

El olor varía de unas especies a otras, incluyendo los suavemente acidulados, con efluvios anisados, con reminiscencias de almendras amargas o francamente desagradable (cual fenol) en algunas especies cuya carne amarillea. La suma de olor desagradable y amarilleamiento de la carne desaconseja su consumo. 

Cultivo en España

El cultivo en España se introdujo en la década de 1970 en la localidad conquense de Villanueva de la JaraVillanueva de la Jara como el resto de la comarca de La Manchuela es la mayor productora de éste hongo en toda España. También se produce gran cantidad de Champiñón en La Rioja, Navarra y en algunas comarcas de León, Zamora y Salamanca.