''Cystoderma carcharias'', is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

agaric An agaric () is a type of fungal fruiting body characterized by the presence of a pileus (cap) that is clearly differentiated from the stipe (stalk), with lamellae (gills) on the underside of the pileus. It is a type of mushroom (or toadstool) ...

in the

fungal A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as one of the tradit ...

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Agaricaceae The Agaricaceae are a family of basidiomycete fungi and include the genus ''Agaricus'', as well as basidiomycetes previously classified in the families Tulostomataceae, Lepiotaceae, and Lycoperdaceae. Taxonomy The family Agaricaceae was publishe ...

. It has a widespread distribution, and has been collected in

coniferous forest Conifers () are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All e ...

s and grasslands in Asia, Europe, North America, and the subantarctic islands. In the field, fruit bodies are characterized by a pink

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. The origin of the word "cap" comes from the Old French word "chapeau" which means "head co ...

up to broad, a well-developed

ring (The) Ring(s) may refer to: * Ring (jewellery), a round band, usually made of metal, worn as ornamental jewelry * To make a sound with a bell, and the sound made by a bell Arts, entertainment, and media Film and TV * ''The Ring'' (franchise), a ...

on the

stem Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

, and an unpleasant odour.

Taxonomy

The species was first described scientifically by

Christian Hendrik Persoon Christiaan Hendrik Persoon (31 December 1761 – 16 November 1836) was a Cape Colony mycologist who is recognized as one of the founders of mycology, mycological Taxonomy (biology), taxonomy. Early life Persoon was born in Cape Colony at ...

, who named it ''Agaricus carcharias'' in 1794. Swiss mycologist

Victor Fayod Victor Fayod (23 November 1860 – 28 April 1900) was a Swiss mycology, mycologist who created an influential novel classification of the agaric Fungus, fungi and described a number of new genera and species. Biographical overview Fayod was b ...

assigned it its current name in 1889. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''carcharias'' is probably derived from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

καρχαρός (''karcharos'') which means sharp, pointed or jagged. καρχαρίας (''karcharias'') is translated as

shark Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...

Description

The

fruiting body The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...

of ''Cystoderma carcharias'' is a relatively small

. The fruiting body is characterised by an off-white and pale pink-tinged

with a distinct darker central spot, and a powdery cuticle. The cap is at first convex, but with maturity becomes flat and slightly

umbonate '' Cantharellula umbonata'' has an umbo. The cap of '' papillate.html" ;"title="Psilocybe makarorae'' is acutely papillate">Psilocybe makarorae'' is acutely papillate. An umbo is a raised area in the center of a mushroom cap. pileus (mycology), ...

. The cap is up to in diameter and may bear a margin fringed with remnants of a

partial veil In mycology, a partial veil (also called an inner veil, to differentiate it from the "outer", or universal veil) is a temporary structure of tissue found on the fruiting bodies of some Basidiomycota, basidiomycete fungus, fungi, typically agarics. ...

. 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 white, adnate and crowded. The

is white and smooth above, and granular below a white, upturned, flared and persistent

. The

is cylindrical and up to tall. 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, ...

is white, firm and full throughout. Additionally, ''C. carcharias'' forma ''album'' is a form recognised as having a snow-white cap. Under a microscope, the

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s are ellipsoid, with dimensions 4–5.5 by 3–4

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

. The spores are white and

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of typically 7–13 nm in diameter, a β-sheet secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the human ...

. The

basidia A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

are 4-spored, club-shaped, and measure 20–25 by 4–6 μm. The fruiting body of ''C. carcharias'' bears a characteristic strong, unpleasant odour. The odour has been described as earthy, muddy and mouldy by various authors. This has been attributed to the presence of the compound

geosmin Geosmin ( ) is an irregular sesquiterpenoid with a distinct earthy or musty odor, which most people can easily smell. The geosmin odor detection threshold in humans is very low, ranging from 0.006 to 0.01 micrograms per liter in water. Geosmin, a ...

. The taste is not distinctive. ''Cystoderma carcharias'' is a fairly common fungus distributed in Europe, North America and

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

Asia, typically occurring in

s. It has also been found on the treeless, Australian subantarctic

Macquarie Island Macquarie Island is a subantarctic island in the south-western Pacific Ocean, about halfway between New Zealand and Antarctica. It has been governed as a part of Tasmania, Australia, since 1880. It became a Protected areas of Tasmania, Tasmania ...

. Fruit bodies are found singly or in groups on soil among grass or moss during late summer and autumn. The fungus is an

acidophilic Acidophiles or acidophilic organisms are those that thrive under highly acidic conditions (usually at pH 5.0 or below). These organisms can be found in different branches of the tree of life, including Archaea, Bacteria,Becker, A.Types of Bacteri ...

litter

saprotroph Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ...

growing frequently under conifers, namely spruce. ''Cystoderma carcharias'' accumulates cadmium in its fruiting bodies. In polluted areas, cadmium concentrations may even exceed 600 mg/kg in dry mass. Intracellular Cd accumulated in sporocarps of ''C. carcharias'' is associated with two isoforms of metallothioneins. Furthermore, ''C. carcharias'' contains numerous organoarsenic compounds from which dimethylarsinoylacetate and trimethylarsoniopropionate have been reported for the first time in the terrestrial environment. This fungus has been deemed inedible by various authors.

References

External links

* *
Scientific images
at BioImages (UK) {{Taxonbar, from=Q2640662 Agaricaceae Fungi of Europe Fungi of North America Fungi of Asia Fungi of Australia Inedible fungi Fungus species