丝膜菌属是丝膜菌科下的一类蘑菇，包含有超过2000个成员物种，广泛分布于世界各地。 该属下的种类有一个共同的特点，即幼年菌株的菌盖和菌柄间有丝膜包被，并由此得名。组成丝膜的菌丝大多是暂时性的，并且在消失后不留下痕迹，个别种类成体的菌柄上可见丝膜的残余。该属成员的孢子印为锈色或棕色。

该属里有几种潜在致命的有毒品种，因此与鹅膏菌属、环柄菇属(Lepiota)和盔孢伞属(Galerina)等齐名，详见致命真菌列表(英文)。这些种类包括尖顶丝膜菌(Cortinarius gentilis)，奥来丝膜菌(Cortinarius orellanus)和细鳞丝膜菌(Cortinarius rubellus，旧称Cortinarius speciosissimus)等，其所含的主要致毒物质是奥来毒素(Orellanine)。

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.