''Agaricus bisporus'' is an

edible An edible item is any item that is safe for humans to eat. "Edible" is differentiated from "eatable" because it does not indicate how an item tastes, only whether it is fit to be eaten. Nonpoisonous items found in nature – such as some mushroo ...

basidiomycete 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, Ba ...

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 ...

native to

grassland A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...

s in

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...

and North America. It has two color states while immature – white and brown – both of which have various names, with additional names for the mature state. ''A. bisporus'' is cultivated in more than seventy countries and is one of the most commonly and widely consumed mushrooms in the world.

Names

When immature and , this mushroom may be known as: * common mushroom * white mushroom * button mushroom * cultivated mushroom * table mushroom * champignon ( French for mushroom) When immature and , it may be known variously as: * Swiss brown mushroom * Roman brown mushroom * Italian brown mushroom * cremini/crimini mushroom * chestnut mushroom (not to be confused with '' Pholiota adiposa'') * baby bella When marketed in its mature state, the mushroom is brown with a cap measuring . This form is commonly sold under the names portobello, portabella, or portobella; the etymology is disputed.

Taxonomy

The common mushroom has a complicated taxonomic history. It was first described by English botanist

Mordecai Cubitt Cooke Mordecai Cubitt Cooke (12 July 1825, in Horning, Norfolk – 12 November 1914, in Southsea, Hampshire) was an English botanist and mycologist who was, at various points, a London schoolteacher, a Kew mycologist, curator at the India Museum, jour ...

in his 1871 ''Handbook of British Fungi'', as a

variety Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

(var. ''hortensis'') of ''

Agaricus campestris ''Agaricus campestris'' is a widely eaten gilled mushroom closely related to the cultivated button mushroom ''Agaricus bisporus''. It is commonly known as the field mushroom or, in North America, meadow mushroom. Taxonomy This species was ori ...

''. Danish mycologist Jakob Emanuel Lange later reviewed a

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

specimen, and dubbed it ''Psalliota hortensis'' var. ''bispora'' in 1926. In 1938, it was promoted to

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 appropriate s ...

status and renamed ''Psalliota bispora''. Emil Imbach (1897–1970) imparted the current scientific name of the species, ''Agaricus bisporus'' after the genus ''Psalliota'' was renamed to ''Agaricus'' in 1946. The specific epithet ''bispora'' distinguishes the two-spored

basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly- ...

from four-spored

varieties Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

Description

The pileus or cap of the original wild species is a pale grey-brown, with broad, flat scales on a paler background and fading toward the margins. It is first hemispherical before flattening out with maturity, and in diameter. The narrow, crowded

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

are free and initially pink, then red-brown, and finally a dark brown with a whitish edge from the

cheilocystidia A cystidium (plural cystidia) is a relatively large cell found on the sporocarp of a basidiomycete (for example, on the surface of a mushroom gill), often between clusters of basidia. Since cystidia have highly varied and distinct shapes that ar ...

. The cylindrical stipe is up to tall by wide and bears a thick and narrow ring, which may be streaked on the upper side. The firm flesh is white, although it stains a pale pinkish-red on bruising. The

spore print 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing pinkish-tan spore print. A 3.5-centimeter ...

is dark brown. The spores are oval to round and measure approximately 4.5–5.5 μm × 5–7.5 μm, and the

usually two-spored, although two-

tetrasporic Tetraspores are red algae spores produced by the tetrasporophytic (diploid) phase in the life history of algae in the Rhodophyta as a result of meiosis.Jones, W.E. Revised and reprinted 1964. A Key to the genera of the British seaweeds.''Field Stu ...

varieties have been described from the

Mojave Desert The Mojave Desert ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily ...

and the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western Europe, Western and Southern Europe and Anatolia, on the south by North Africa ...

, with predominantly

heterothallic Heterothallic species have sexes that reside in different individuals. The term is applied particularly to distinguish heterothallic fungi, which require two compatible partners to produce sexual spores, from homothallic ones, which are capable ...

and

homothallic Homothallic refers to the possession, within a single organism, of the resources to reproduce sexually; i.e., having male and female reproductive structures on the same thallus. The opposite sexual functions are performed by different cells of a si ...

lifestyles, respectively. This mushroom is commonly found worldwide in fields and grassy areas following rain, from late spring to autumn, especially in association with

manure Manure is organic matter that is used as organic fertilizer in agriculture. Most manure consists of animal feces; other sources include compost and green manure. Manures contribute to the Soil fertility, fertility of soil by adding organic ma ...

. It is widely collected and eaten in many parts of the world; however, it resembles deadly or poisonous lookalikes (see below).

Lookalike species

The common mushroom could be confused with young specimens of the deadly poisonous

destroying angel The name destroying angel applies to several similar, closely related species of deadly all-white mushrooms in the genus ''Amanita''. They are '' Amanita bisporigera'' and '' A. ocreata'' in eastern and western North America, respectively, and '' ...

(''Amanita'' sp.), but the latter may be distinguished by their volva or cup at the base of the mushroom and pure white gills (as opposed to pinkish or brown of ''A. bisporus''). A more common and less dangerous mistake is to confuse ''A. bisporus'' with ''

Agaricus xanthodermus ''Agaricus xanthodermus'', commonly known as the yellow-staining mushroom or simply the yellow-stainer, is a mushroom of the genus ''Agaricus'', which displays a strong yellow colouration at the base of the stem when cut. It is poisonous for mos ...

'', an inedible mushroom found worldwide in grassy areas. ''A. xanthodermus'' has an odor reminiscent of

phenol Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it ...

; its flesh turns yellow when bruised. This fungus causes

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

and vomiting in some people. The poisonous European species ''

Entoloma sinuatum ''Entoloma sinuatum'' ( commonly known as the livid entoloma, livid agaric, livid pinkgill, leaden entoloma, and lead poisoner) is a poisonous mushroom found across Europe and North America. Some guidebooks refer to it by its older scientific ...

'' has a passing resemblance but has yellowish gills, turning pink, and lacks a ring.

Cultivation history

The earliest scientific description of the commercial cultivation of ''A. bisporus'' was made by French botanist

Joseph Pitton de Tournefort Joseph Pitton de Tournefort (5 June 165628 December 1708) was a French botanist, notable as the first to make a clear definition of the concept of genus for plants. Botanist Charles Plumier was his pupil and accompanied him on his voyages. Lif ...

in 1707. French agriculturist Olivier de Serres noted that transplanting mushroom

mycelia 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 ...

would lead to the propagation of more mushrooms. Originally, cultivation was unreliable as mushroom growers would watch for good flushes of mushrooms in fields before digging up the mycelium and replanting them in beds of composted manure or inoculating 'bricks' of compressed litter, loam, and manure. Spawn collected this way contained pathogens, and crops would be infected or not grow. In 1893, sterilized, or pure culture, spawn was discovered and produced by the

Pasteur Institute The Pasteur Institute (french: Institut Pasteur) is a French non-profit private foundation dedicated to the study of biology, micro-organisms, diseases, and vaccines. It is named after Louis Pasteur, who invented pasteurization and vaccines ...

in Paris for cultivation on composted horse manure. Modern commercial varieties of the common agaricus mushroom were originally light brown. The white mushroom was discovered in 1925 growing among a bed of brown mushrooms at the Keystone Mushroom Farm in Coatesville,

Pennsylvania Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...

. Louis Ferdinand Lambert, the farm's owner and a mycologist by training, brought the white mushroom back to his laboratory. As with the reception of white bread, it was seen as a more attractive food item and became grown and distributed. Similar to the commercial development history of the navel orange and Red Delicious apple, cultures were grown from the mutant individuals. Most cream-colored store mushrooms marketed today are products of this 1925 chance natural mutation. ''A. bisporus'' is now cultivated in at least seventy countries worldwide. In the U.S., the white button form of ''A. bisporus'' alone accounts for about 90% of mushrooms sold.

Nutritional profile

In a 100-gram serving, raw white mushrooms provide of

food energy Food energy is chemical energy that animals (including humans) derive from their food to sustain their metabolism, including their muscular activity. Most animals derive most of their energy from aerobic respiration, namely combining the carbohy ...

and are an excellent source (> 19% of the

Daily Value The Reference Daily Intake (RDI) used in nutrition labeling on food and dietary supplement products in the U.S. and Canada is the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97–98% of healthy ...

, DV) of the

B vitamins B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism and synthesis of red blood cells. Though these vitamins share similar names (B1, B2, B3, etc.), they are chemically distinct compounds that often coexi ...

, riboflavin, niacin, and

pantothenic acid Pantothenic acid, also called vitamin B5 is a water-soluble B vitamin and therefore an essential nutrient. All animals require pantothenic acid in order to synthesize coenzyme A (CoA) – essential for fatty acid metabolism – as well as to, ...

(table). Fresh mushrooms are also a good source (10–19% DV) of the dietary mineral

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

(table). While fresh ''A. bisporus'' only contains 0.2 micrograms (8 IU) of

vitamin D Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...

ergocalciferol Ergocalciferol, also known as vitamin D2 and nonspecifically calciferol, is a type of vitamin D found in food and used as a dietary supplement. As a supplement it is used to prevent and treat vitamin D deficiency. This includes vitamin D defici ...

(vitamin D2), the ergocalciferol content increases substantially after exposure to UV light.

Gallery

File:Agaricus bisporus Zuchtchampignon2.jpg, White ''Agaricus bisporus'' File:Champignonnière Jodogne grotte Heyoule Eben Bassenge 01.jpg, Brown variety grown in an underground quarry File:Agaricus bisporus (Cup mushroom, doubled).jpg, Two ''Agaricus bisporus'' mushrooms that have fused together File:Portobello mushrooms.jpg, Portobello mushrooms File:Giant mushroom cross-section.jpg, Cross-section of a portobello cultivar File:Giant mushroom underside.jpg, Ventral view of a portobello cultivar with a bisected stipe File:2014 11 Portobello rocket feta toasted baguette.jpg, Grilled portobello,

feta Feta ( el, φέτα, ) is a Greek brined white cheese made from sheep's milk or from a mixture of sheep and goat's milk. It is soft, with small or no holes, a compact touch, few cuts, and no skin. Crumbly with a slightly grainy texture, it ...

, and

rocket A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely fr ...

salad on toasted

baguette A baguette (; ) is a long, thin type of bread of French origin that is commonly made from basic lean dough (the dough, though not the shape, is defined by French law). It is distinguishable by its length and crisp crust. A baguette has a dia ...