Inocybe is a large genus of mushroom-forming fungi with over 1400 species, including all forms and varieties.

Members of Inocybe are mycorrhizal, and some evidence shows that the high degree of speciation in the genus is due to adaptation to different trees and perhaps even local environments.

It is taken from the Greek words ἴς (in the genitive ἴνος, meaning "muscle, nerve, fiber, strength, vigor") and κύβη ("head").

[2] The genus was first described as Agaricus tribe Inocybe by Swedish scholar Elias Magnus Fries in volume 1 of his work, Systema mycologicum (1821), and verified in the volume 2 of his book Monographia Hymenomycetum Sueciae in 1863.

[3] Typical mushrooms of the genus have various shades of brown, although some lilac or purplish species exist.

Caps are small and conical, though flattening somewhat in age, generally with a pronounced central umbo.

In fact, Inocybe is the most commonly encountered mushroom genus for which microscopic characteristics are the only means of certain identification to the species level.

The stipe base is (generally) not bulbous and a remnant of a cortina is present in the margin of the young cap.

Several genera are recognized within the family Inocybaceae: Inocybe This subgenus has pleurocystidia, usually thick-walled and in the apex has crystals.

Inosperma The fruiting bodies of this subgenus usually have a distinct odor (fruity, honey-like, fishy).