Cortinarius

Cortinarius is a genus of mushrooms. It is suspected to be the largest genus of agarics, containing over 2000 different species and found worldwide. 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. All also have a rusty brown spore print. The common names cortinar and webcap refer to members of the genus.

Distinguishing features
The veil protects the gills in younger specimens and usually disappears leaving little to no trace of itself as the mushroom grows. The spores of a Cortinarius mushroom are rusty 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 mycorrhizae.

Many mushrooms in the genus - for example Cortinarius sanguineus and other species in section Dermocybe - are beautiful and colourful and are often used for dyeing.

Toxicity
Several mushrooms in the genus Cortinarius are poisonous. Some are even lethal, such as Cortinarius rubellus and Cortinarius orellanus. Therefore, a common rule when it comes to mushrooms from this genus are that none of them should be eaten or even tasted. However, it should be noted that 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 is easy to detect because it is fluorescent. It has been found in at least 34 Cortinariaceae. 

Classification
Recently, molecular 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.

Some consider the subgenus Dermocybe to have generic status.

Species

 * Cortinarius austrovenetus - also known as Dermocybe austroveneta or Green Skin-head is an Australian fungus typical of the brightly coloured Dermocybe subgenus.
 * Cortinarius orellanus and C. rubellus are two of the deadly webcaps found in Europe and North America.