''Agaricus bitorquis'' 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 ...

white

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 ...

of the genus ''

Agaricus ''Agaricus'' is a genus of mushrooms containing both edible and poisonous species, with over 400 members worldwide and possibly again as many disputed or newly-discovered species. The genus includes the common ("button") mushroom ('' Agaricus bi ...

'', similar to the common button mushroom that is sold commercially. The name supersedes ''Agaricus rodmani''. It is also commonly known as torq, the banded agaric, spring agaric, or pavement mushroom, as it has been recorded pushing up paving slabs.

Taxonomy

The specific epithet ''bitorquis'' is

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

"having two collars", and refers to the two rings resulting from detachment of the

veil A veil is an article of clothing or hanging cloth that is intended to cover some part of the head or face, or an object of some significance. Veiling has a long history in European, Asian, and African societies. The practice has been prominent ...

from both the top and bottom of the stipe. The species was first defined by the French mycologist

Lucien Quélet Lucien Quélet in 1869 Lucien Quélet (14 July 1832 – 25 August 1899) was a French naturalist and mycologist. Quélet discovered several species of fungi and was the founder of the Société mycologique de France, a society devoted to mycolo ...

in 1884, in the form of ''Psalliota bitorquis'' (using another genus name in place of the modern ''Agaricus'').

Description

The

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...

is dry, smooth, and white (but stains yellowish in age), and measures 4 to 15 cm in diameter, convex to flat, often with dirt on the cap. The

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, very narrow and close. They are a light pink color when young, becoming dark reddish-brown as the spores mature. 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 chocolate brown. The stipe is 3–11 cm long, 1–4 cm thick, cylindrical to clavate (club-shaped), stout, white, smooth, with a membranous veil and thick white mycelial sheathing near the base. Distinctively it has both a thick upper ring which is shaped like a funnel and a thinner skirt-like lower ring, giving rise to the species name ''bitorquis''. The

flesh Flesh is any aggregation of soft tissues of an organism. Various multicellular organisms have soft tissues that may be called "flesh". In mammals, including humans, ''flesh'' encompasses muscles, fats and other loose connective tissues, but ...

is solid and firm, with a mild odor. It is often confused with the briny-smelling '' Agaricus bernardii''. It also resembles ''

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 ...

'' somewhat, but that species only has a single fragile ring.

Microscopic details

Basidiospore A basidiospore is a reproductive spore produced by Basidiomycete fungi, a grouping that includes mushrooms, shelf fungi, rusts, and smuts. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are ...

s are elliptical in shape, smooth, and with dimensions of 5–7 x 4–5.5 µm.

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- ...

are 20–25 x 6.5–8.5 µm, usually four-spored, but often with two-spored basidia present.

Cystidia 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 ...

are present and numerous.

Distribution and habitat

''Agaricus bitorquis'' may be found growing solitary or in small groups in gardens (noted as growing in a

gregarious Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother wasp ...

manner), and at roadsides, usually on the pavement, often where salt is applied to combat ice in winter. Pushing through asphalt and slabs, it is subterranean, and often matures underground. It is occasional throughout North America, Europe, Asia and Australia.

Edibility

''Agaricus bitorquis'' is a choice edible species, with a typical 'mushroomy' taste. Specimens collected in the wild may be gritty due to its often subterranean habitat. As with all specimens picked from the wild, care should be taken to consider the suitability of the collection site, as this species can bioaccumulate toxic heavy metals, especially lead, from polluted areas. Nutritional analysis has shown this species to contain 18 amino acids, including all of the essential ones.

Cultivation

First cultivated commercially in 1968, ''A. bitorquis'' has several growth characteristics that have piqued the interest of mushroom cultivators looking for an alternative to the standard button mushroom, '' A. bisporus''. For example, ''A. bitorquis'' is more resistant to various viral diseases, can grow at higher temperatures and CO₂ concentrations, and has better resistance to bruising. Furthermore, high temperature-resistant strains have recently been developed which may help cultivators overcome problems associated with cooling production rooms during hot summer months.Sharma, S.S., Doshi, A. (2001). High temperature tolerant button mushroom (''Agaricus bitorquis'') and its strains suitable under Rajasthan conditions. ''J Mycol Plant Pathol''. 31(2):256–7.

References

External links

Mushroom-Collecting.com - ''Agaricus bitorquis''

Index Fungorum
listing of synonyms
Roger's Mushrooms
picture and description
Mushroom Observer
various photos

{{Taxonbar, from=Q1423834 bitorquis Edible fungi Fungi described in 1884 Fungi of Europe Fungi of North America Taxa named by Lucien Quélet