Agaricus xanthodermus
Encyclopedia
Agaricus xanthodermus, commonly known as the yellow-staining mushroom, 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 most people, causing gastrointestinal upsets but is eaten by some without apparent negative effect.
words for "yellow-skinned"; this is the name used by many authorities, such as Index Fungorum. However the form Agaricus xanthoderma is also often seen,
and in fact this is more correct in classical terms; here -derma (δέρμα) is a Greek neuter noun, not an adjective which would agree in gender with Agaricus.
is generally 6–10 cm (2.4–4 in) in diameter, though can reach 15 cm (6 in). It is initially convex, with some young specimens having a squarish shape, though flattening with age. It is whitish, with light brown tints towards the centre. The cap is dry and smooth, but can be scaly when old. The gills of this mushroom progress from pale-pink to a chocolate color. The spore print is brown. Its white stipe
is bulbous with a skirt-like ring. Microscopically, there are club-shaped cheilocystidia
. The spores are 6-7×3-4 µm
.
The main identifying feature is an immediate bright yellow colouration on cutting through the base of the stem, or scraping the flesh; later the affected area fades to a dull brown. Numerous edible Agaricus species, such as A. augustus
, A. arvensis
and A. silvicola
, turn yellow to a greater or lesser extent, but they do not display such an intense reaction.
Agaricus xanthodermus has an unpleasant characteristic smell, which is phenolic, that is reminiscent of ink or carbolic soap
. The smell is especially strong at the base of the stem. On cooking the smell becomes very noticeable, and this may deter people from eating it inadvertently.
, West Asia (Iran) and Europe
, and is also found in North Africa, and eastern Anatolia
in Turkey, and has been introduced into Australia
. It occurs in woods, lawns, gardens and hedgerows in autumn. This is a saprobic species.
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
of the
genus Agaricus
Agaricus
Agaricus is a large and important genus of mushrooms containing both edible and poisonous species, with possibly over 300 members worldwide...
, which displays a strong yellow colouration at the base of the stem when cut. It is poisonous for most people, causing gastrointestinal upsets but is eaten by some without apparent negative effect.
Taxonomy
The yellow-staining mushroom was officially described in 1876. The epithet xanthodermus is derived from the Ancient GreekAncient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
words for "yellow-skinned"; this is the name used by many authorities, such as Index Fungorum. However the form Agaricus xanthoderma is also often seen,
and in fact this is more correct in classical terms; here -derma (δέρμα) is a Greek neuter noun, not an adjective which would agree in gender with Agaricus.
Description
The capPileus (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 generally 6–10 cm (2.4–4 in) in diameter, though can reach 15 cm (6 in). It is initially convex, with some young specimens having a squarish shape, though flattening with age. It is whitish, with light brown tints towards the centre. The cap is dry and smooth, but can be scaly when old. The gills of this mushroom progress from pale-pink to a chocolate color. The spore print is brown. Its white 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 bulbous with a skirt-like ring. Microscopically, there are club-shaped cheilocystidia
Cystidium
A cystidium is a relatively large cell found on the hymenium of a basidiomycete , often between clusters of basidia. Since cystidia have highly varied and distinct shapes that are often unique to a particular species or genus, they are a useful micromorphological characteristic in the...
. The spores are 6-7×3-4 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...
.
The main identifying feature is an immediate bright yellow colouration on cutting through the base of the stem, or scraping the flesh; later the affected area fades to a dull brown. Numerous edible Agaricus species, such as A. augustus
Agaricus augustus
Agaricus augustus, known commonly as the prince, is a basidiomycete fungus of the genus Agaricus.-Taxonomy:According to Heinemann's popular division of Agaricus, A. augustus belongs to section Arvenses. The system proposed by Wasser classifies A. augustus within subgenus Flavoagaricus, section...
, A. 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...
and A. silvicola
Agaricus silvicola
Agaricus silvicola, also known as the Wood Mushroom is a species of Agaricus mushroom related to the button mushroom.- Description :...
, turn yellow to a greater or lesser extent, but they do not display such an intense reaction.
Agaricus xanthodermus has an unpleasant characteristic smell, which is phenolic, that is reminiscent of ink or carbolic soap
Carbolic soap
Carbolic soap is a mildly disinfectant soap containing carbolic acid . Once widely available in the United States and the most common disinfectant cleaner in hospitals, it has disappeared from all but specialty retail stores. It is distributed to disaster victims for routine hygiene by the Red...
. The smell is especially strong at the base of the stem. On cooking the smell becomes very noticeable, and this may deter people from eating it inadvertently.
Distribution and habitat
This mushroom is very common and widely distributed in North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, West Asia (Iran) and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, and is also found in North Africa, and eastern Anatolia
Anatolia
Anatolia is a geographic and historical term denoting the westernmost protrusion of Asia, comprising the majority of the Republic of Turkey...
in Turkey, and has been introduced into Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. It occurs in woods, lawns, gardens and hedgerows in autumn. This is a saprobic species.
Related species
A. xanthodermus belongs to a group of related species (the "Xanthodermatei") which likewise discolour bright yellow and have a phenolic smell. They include A. praeclaresquamosus (formerly A. placomyces) which has dark grey scales, and A. pilatianus which does not have a bulbous stem.External links
- “Agaricus xanthodermus” by Robert Sasata, Healing-Mushrooms.net, November, 2007.