''Cortinarius'' is a globally distributed

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

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 ...

s in the family Cortinariaceae. It is suspected to be the largest genus of

agaric An agaric () is a type of fungus 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. In the UK, agarics are called "mushroom ...

s, containing over 2,000 widespread species. A common feature among all species in the genus ''Cortinarius'' is that young specimens have a cortina (veil) between the cap and the stem, hence the name, meaning ''curtained''. Most of the fibres of the cortina are ephemeral and will leave no trace once gone, except for limited remnants on the stem or cap edge in some species. All have a rusty brown spore print. The

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

s cortinar and webcap refer to members of the genus. Due to dangerous toxicity of several species (such as ''

Cortinarius orellanus ''Cortinarius orellanus'', commonly known as the fool's webcap or fools webcap, is a species of deadly fungus in the family Cortinariaceae native to Europe. Within the genus it belongs to a group known as the Orellani, all of which are highly t ...

'') and the fact that it is difficult to distinguish between various species of the genus, non-expert consumption of mushrooms from the genus is discouraged.

Distinguishing features

The veil protects 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 ...

in younger specimens and usually disappears leaving little to no trace of itself as the mushroom grows. The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

s of a ''Cortinarius'' mushroom are rust brown to brownish red in color. It is usually possible to identify a mushroom as being a member of the genus, but extremely difficult to positively identify the species as many of the species are nearly identical. All mushrooms in this genus form

mycorrhiza A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, mycorrhiza or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plan ...

e. Many mushrooms in the genus, for example '' Cortinarius sanguineus'' and other species in section ''

Dermocybe The fungi of the ''Dermocybe'' group, commonly known as skin-heads, form a group within the huge genus ''Cortinarius''. They are generally considered to be a subgenus though some authorities consider them to form a genus in their own right. The ...

'', are colourful and are often used for

dyeing Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular c ...

Toxicity

Several mushrooms in the genus ''Cortinarius'' are

poison Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...

ous, mainly because they cause acute tubulointerstitial nephritis. Some are even lethal, such as ''

Cortinarius rubellus ''Cortinarius rubellus'', commonly known as the deadly webcap, is a species of fungus in the family Cortinariaceae, native to high-latitude temperate to subalpine forests of Eurasia and North America. Within the genus it belongs to a group known ...

'' and ''

''. Therefore, a common rule when it comes to mushrooms from this genus is that none of them should be eaten. Many Cortinarius varieties can be mistaken for other edible mushrooms (such as the Blewit Mushroom) and should therefore be researched extensively before you consider ingesting a look alike of this genus. However, some species—notably the giant of the genus, '' Cortinarius praestans'' and the gypsy mushroom ('' Cortinarius caperatus'')—are edible and appreciated in several European countries. The toxin in ''Cortinarius'' species,

orellanine Orellanine or orellanin is a mycotoxin found in a group of mushrooms known as the Orellani of the family Cortinariaceae. Structurally, it is a bipyridine N-oxide compound somewhat related to the herbicide diquat. History Orellanine first came t ...

is easy to detect because it is fluorescent. It has been found in at least 34 Cortinariaceae.

Classification

Molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bio ...

studies of members of the genus ''Rozites'', including its most famous member ''R. caperata'', have shown them nested within ''Cortinarius'' and have been sunk into this genus. This genus was erected on the basis of a double veil, yet its members do not form a discrete lineage and lie nested within ''Cortinarius''. Hence the genus is no longer recognised. Some consider the subgenus ''Dermocybe'' to have generic status. It does form a single lineage, but lies within ''Cortinarius'' so the consensus has been to sink it into the larger genus.

Selected species

*'' Cortinarius austrovenetus'' - also known as ''Dermocybe austroveneta'' or green skin-head is an Australian fungus typical of the brightly coloured ''

'' subgenus. *'' Cortinarius caperatus'', the "gypsy mushroom", is an edible mushroom found in northern regions of Europe and North America. *''

'' and '' C. rubellus'' are two of the deadly webcaps found in Europe and North America.

References

{{Taxonbar, from=Q306495 Agaricales genera