Clitocybe dealbata, also known as the ivory funnel, is a small white funnel-shaped basidiomycete fungus widely found in lawns, meadows and other grassy areas in Europe and North America.

Clitocybe dealbata was initially described by British naturalist James Sowerby in 1799 as Agaricus dealbatus,[2] its specific epithet derived from the Late Latin verb dealbare 'to whitewash',[3] inexorably calling to mind the Biblical "whited sepulchre", that is outwardly pleasing but inwardly toxic.

[4] However, this species is often considered a synonym of Clitocybe rivulosa[5] and according to Bon[6] the name C. dealbata may be invalid (a nomen dubium) as James Sowerby's definition conflicts with Elias Magnus Fries's.

[12] The main toxic component of Clitocybe dealbata is muscarine, and thus the symptoms are like those of nerve agent poisoning, namely greatly increased salivation, sweating (perspiration), and the flow of tears (lacrimation) within 15–30 minutes of ingestion.

With large doses, these symptoms may be followed by abdominal pain, severe nausea, diarrhea, blurred vision, and labored breathing.