Agaricus campestris
Encyclopedia
Agaricus campestris is commonly known as the field mushroom or, in North America, meadow mushroom. It is a widely eaten gilled mushroom
Agaricales
The fungal order Agaricales, also known as gilled mushrooms , or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13000 described species, along with five extinct genera known only from the fossil record...

 closely related to the cultivated button mushroom
Button mushroom
Agaricus bisporus—known variously as the common mushroom, button mushroom, white mushroom, table mushroom, champignon mushroom, crimini mushroom, Swiss brown mushroom, Roman brown mushroom, Italian brown, Italian mushroom, cultivated mushroom, or when mature, the Portobello mushroom—is an edible...

 Agaricus bisporus.

Taxonomy

This species was originally noted and named in 1753 by Carolus Linnaeus
Carolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...

 as Agaricus campestris. It was placed in the genus Psalliota by Lucien Quelet
Lucien Quélet
thumb|Lucien QuéletLucien Quélet was a French mycologist and naturalist who discovered several species and was the founder of the Société mycologique de France, a society devoted to mycological studies....

 in 1872. Some variants have been isolated over the years, a few of which now have species status, for example, Agaricus bernardii
Agaricus bernardii
Agaricus bernardii,commonly called Salt-Loving Agaricus is a mushroom in the Agaricaceae family of fungi. It partially resembles Agaricus bitorquis but it differs from that fungus by the reddish-brown staining of cap and stipe tissue as well as its briny odour...

Quel. (1878), Agaricus bisporus (J.E. Lange) Imbach (1946), Agaricus bitorquis
Agaricus bitorquis
Agaricus bitorquis is an edible white mushroom of the genus Agaricus, similar to the common button mushroom that is sold commercially. The name supersedes Agaricus rodmani...

(Quel.) Sacc. (1887), Agaricus cappellianus Hlavacek (1987), and Agaricus silvicola
Agaricus silvicola
Agaricus silvicola, also known as the Wood Mushroom is a species of Agaricus mushroom related to the button mushroom.- Description :...

(Vittad.) Peck (1872).
Some were so similar they did not warrant even variant status, others have retained it e.g. Agaricus campestris var. equestris (F.H. Moller) Pilat (1951) is still valid, and presumably favors pasture where horses have been kept. Agaricus campestris var isabellinus (F.H. Moller) Pilat (1951), and Agaricus campestris var.radicatus, are possibly still valid too.
The specific epithet campestris is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 campus "field".

Description

The cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...

 is white, may have fine scales, and is 5 to 10 cm (2 to 3.9 in) in diameter; it is first hemispherical in shape before flattening out with maturity. The gills are initially pink, then red-brown and finally a dark brown, as is the spore print
Spore print
thumb|300px|right|Making a spore print of the mushroom Volvariella volvacea shown in composite: mushroom cap laid on white and dark paper; cap removed after 24 hours showing pinkish-tan spore print...

. The 3 to 10 cm (1.2 to 3.9 in) tall stipe
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...

 is predominately white and bears a single thin ring. The taste is mild. The white flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....

 bruises slightly reddish, as opposed to yellow in the inedible (and somewhat toxic) Agaricus xanthodermus
Agaricus xanthodermus
Agaricus xanthodermus, commonly known as the yellow-staining mushroom, is a mushroom of thegenus Agaricus, which displays a strong yellow colouration at the base of the stem when cut...

and similar species. The spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

s are 7–8 by 4–5 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...

, and ovate. Cheilocystidia are absent.

Similar species:

Amanita virosa
Amanita virosa
Amanita virosa, commonly known as the European destroying angel, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in Europe, A. virosa associates with various deciduous and coniferous trees...

(and similar, closely related species), the destroying angel (morbidly toxic).

Agaricus xanthodermus
Agaricus xanthodermus
Agaricus xanthodermus, commonly known as the yellow-staining mushroom, is a mushroom of thegenus Agaricus, which displays a strong yellow colouration at the base of the stem when cut...

, the yellow stainer (causes gastrointestinal problems).

Agaricus arvensis
Agaricus arvensis
Agaricus arvensis, commonly known as the Horse Mushroom, is a mushroom of the genus Agaricus.-Taxonomy:Described as Agaricus arvensis by Jacob Christian Schaeffer in 1762, and given numerous binomial descriptions since. Its present name arvensis means 'of the field'.-Description:The cap is similar...

, the horse mushroom (excellent edible).

White Clitocybe
Clitocybe
Hundreds of species of mushrooms compose the fungus genus Clitocybe. They are characterized by white, off-white, buff, cream, pink, or light-yellow spores, gills running down the stem, and pale white to brown or lilac coloration. They are primarily saprotrophic, decomposing forest ground litter...

species, that also grow on lawns, and in grassy places (dangerous).

Distribution and habitat

Agaricus campestris is common in fields and grassy areas after rain from late summer onwards worldwide. It is often found on lawns in suburban areas. Appearing in small groups, in fairy rings, or solitary. Owing to the demise of horse drawn vehicles, and the subsequent decrease in the number of horses on pasture, the old 'white outs' of years gone by are becoming rare events. This species is rarely found in woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...

.

Edibility

It is widely collected and eaten, even by those who would not normally eat wild mushrooms. This mushroom is not commercially cultivated on account of its fast maturing and short shelf-life.
Culinary uses of the meadow mushroom include eating it sauteed or fried, in sauces, or even sliced raw and included in salads. In flavor and texture, this mushroom is almost identical to the white button mushroom available in grocery stores in the United States. Be sure to rinse well to dislodge any sand, and also watch out for small, white larvae which tunnel through the stems and caps. Among the similar species mentioned above, there have been cases (in fact the most common cause of fatal fungus poisoning in france) where the deadly toxic destroying angel
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, and A. virosa in Europe. Another very similar species, A. verna or fool's mushroom was...

 (Amanita bisporigera) has been consumed by individuals who mistook it for this species. The edibility of specimens collected from lawns is uncertain because of possible contamination with pesticides or other chemicals.

Other uses

Research into fungal dressings for the treatment of ulcers, and bed sores, using fungal mycelial filaments, is ongoing. In the past, slices of A. campestris were applied to scalds, and burns in parts of Scotland.

Bioactive properties

Water extracts of A. campestris have been shown to enhance the secretion of insulin
Insulin
Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....

, and to have insulin-like effects on glucose metabolism in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...

, although the mechanism is not understood.

External links

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