What is "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, meaning curtained. Most of the fibers of the cortina are ephemeral and will leave no trace once gone, except for limited remnants on the stem in some species. All have a rusty brown spore print. The common names cortinar and webcap refer to members of the genus. Due to dangerous toxicity of several species (such as Cortinarius orellanus) and the fact that it's difficult to distinguish between various species of the genus, non-expert consumption of mushrooms from the genus is discouraged.