When immature and
white, this mushroom may be known as
common mushroom,
button mushroom,
white mushroom,
cultivated mushroom,
table mushroom, and
champignon mushroom. When immature and
brown, this mushroom may be known variously as
Swiss brown mushroom,
Roman brown mushroom,
Italian brown,
Italian mushroom,
cremini or
crimini mushroom,
baby bella,
brown cap mushroom, or
chestnut mushroom.
[2]
A. bisporus is
cultivated in more than seventy countries,
[3] and is one of the most commonly and widely consumed mushrooms in the world.
Taxonomy[edit]
Description[edit]
The
pileus or cap of the original wild species is a pale grey-brown in color, with broad, flat scales on a paler background and fading toward the margins. It is first hemispherical in shape before flattening out with maturity, and 5–10 centimetres (2–4 inches) in diameter. The narrow, crowded
gills are free and initially, pink, then red-brown and finally a dark brown with a whitish edge from the
cheilocystidia. The cylindrical
stipe is up to 6 cm (
2 1⁄3 in) tall by 1–2 cm wide and bears a thick and narrow
ring, which may be streaked on the upper side. The firm flesh is white, although stains a pale pinkish-red on bruising.
[8][9] The
spore print is dark brown. The spores are oval to round and measure approximately 4.5–5.5 μm × 5–7.5 μm, and the
basidia usually two-spored, although two-tetrasporic varieties have been described from the
Mojave Desert and the
Mediterranean, with predominantly
heterothallic and
homothallic lifestyles, respectively.
[10][11]
This mushroom is commonly found worldwide in fields and grassy areas following rain, from late spring through to autumn, especially in association with
manure. It is widely collected and eaten, even by those who would not normally experiment with
mushroom hunting.
[9]
Similar species[edit]
The common mushroom could be confused with young specimens of the deadly poisonous
destroying angel (
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). Thus it is always important to clear away debris and examine the base of such similar mushrooms, as well as cutting open young specimens to check the gills. Furthermore, the destroying angel grows in
mossy woods and lives symbiotically with
spruce.
A more common and less dangerous mistake is to confuse
A. bisporus with
Agaricus xanthodermus, an inedible mushroom found worldwide in grassy areas.
A. xanthodermus has an odor reminiscent of
phenol; its flesh turns yellow when bruised. This fungus causes
nausea and vomiting in some people.
The poisonous European species,
Entoloma sinuatum, has a passing resemblance as well, but has yellowish gills, turning pink, and it lacks a ring.
Cultivation history[edit]
A. bisporus being cultivated
The earliest scientific description of the commercial cultivation of
A. bisporus was made by French botanist
Joseph Pitton de Tournefort in 1707.
[12] French agriculturist
Olivier de Serres noted that transplanting mushroom
mycelia 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 commonly, would be infected, or not grow at all.
[13] In 1893, sterilized, or pure culture, spawn was discovered and produced by the
Pasteur Institute in Paris, for cultivation on composted horse manure.
[14]
Today's commercial variety of the common mushroom originally was a light brown color. In 1926, a
Pennsylvania mushroom farmer found a clump of common mushrooms with white caps in his mushroom bed. As with the reception of white bread, it was seen as a more attractive food item and became very popular.
[15] Similar to the commercial development history of the
navel orange and
Red Delicious apple, cultures were grown from the mutant individuals, and most of the cream-colored store mushrooms marketed today are products of this 1926 chance natural mutation.
A. bisporus is now cultivated in at least seventy countries throughout the world.
[3] Global production in the early 1990s was reported to be more than 1.5 million tons, worth more than US$2 billion.
[16]
Nutritional profile[edit]
Research[edit]
Mushrooms contain
hydrazine derivatives, including
agaritine and
gyromitrin, that have been evaluated for
carcinogenic activity.
[19] Agaritine, a hydrazine, poses no toxicological risk to humans when mushrooms are consumed in typical amounts.
[20]
Gallery[edit]
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Cross-section of a portobello cultivar
Ventral view of a portobello cultivar with a bisected
stipe
Two Agaricus bisporus mushrooms that have fused together
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See also[edit]
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