# Clitocybe dealbata
**Clitocybe dealbata** (Sowerby) P. Kumm. is a small, white, muscarine-containing grassland mushroom in the family Clitocybaceae, known in English as the Ivory Funnel. It was described by James Sowerby as *Agaricus dealbatus* in 1799 and transferred to *Clitocybe* by Paul Kummer in 1871 in *Der Führer in die Pilzkunde*, page 121.[1](https://www.indexfungorum.org/Names/namesrecord.asp?RecordId=216184) • [2](https://www.nhm.ac.uk/our-science/data/uk-species/taxon?tvk=NHMSYS0001477986) The species is deadly poisonous, and its resemblance to edible lawn fungi makes it one of the most significant causes of mushroom poisoning in Europe and North America.
| Key fact | Detail |
|---|---|
| Name | *Clitocybe dealbata* (Sowerby) P. Kumm., Führ. Pilzk. (Zerbst): 121 (1871); basionym *Agaricus dealbatus* Sowerby 1799[1](https://www.indexfungorum.org/Names/namesrecord.asp?RecordId=216184) |
| Common name | Ivory Funnel (English); also listed as Sweating Mushroom[2](https://www.nhm.ac.uk/our-science/data/uk-species/taxon?tvk=NHMSYS0001477986) • [3](https://www.gbif.org/species/2531056) |
| Classification | Clitocybaceae, Agaricales, Agaricomycetes, Basidiomycota[1](https://www.indexfungorum.org/Names/namesrecord.asp?RecordId=216184) |
| Toxicity | Contains up to 0.15% muscarine; ingestion causes illness characterized primarily by profuse sweating[4](https://www.fda.gov/files/food/published/Bad-Bug-Book-2nd-Edition-%28PDF%29.pdf) • [18](https://davidmoore.org.uk/21st_Century_Guidebook_to_Fungi_PLATINUM/REPRINT_collection/Michelot_etal_A.muscaria_chemistry_biology_toxicology.pdf) |
| Habitat and form | Grassland, in troops or rings; flatter, paler caps 2 to 5 cm across[5](https://www.coford.ie/media/coford/content/publications/ForestFungiinIreland2008160919.pdf) |
| Taxonomic status | Treated by some authorities as a synonym of *Clitocybe rivulosa* (Pers.) P. Kumm.[6](https://nzor.org.nz/names/2bb94e49-8814-4379-b9bc-95a1ddce523d) |
## Nomenclature and classification
The basionym *Agaricus dealbatus* was published by Sowerby in 1799, with Elias Fries as sanctioning author, and the current combination appeared in Kummer's 1871 *Führer in die Pilzkunde*.[1](https://www.indexfungorum.org/Names/namesrecord.asp?RecordId=216184) Index Fungorum places the species in Clitocybaceae within the [Agaricales](https://www.edgepedia.org/agaricales), Agaricomycetes, and [Basidiomycota](https://www.edgepedia.org/basidiomycota).[1](https://www.indexfungorum.org/Names/namesrecord.asp?RecordId=216184) GBIF's backbone taxonomy instead places it in [Tricholomataceae](https://www.edgepedia.org/tricholomataceae), a family whose boundaries have shifted repeatedly across classifications of this group.[3](https://www.gbif.org/species/2531056)
**Relationship to Clitocybe rivulosa.** The distinction between *C. dealbata* and *C. rivulosa*, the Fool's Funnel, is generally considered dubious, because macroscopic and microscopic differences, if evident at all, are minimal.[7](https://www.first-nature.com/fungi/clitocybe-rivulosa.php) New Zealand's NZOR and Biota of NZ databases treat *C. dealbata* as a synonym of *Clitocybe rivulosa* (Pers.) P. Kumm. 1871.[6](https://nzor.org.nz/names/2bb94e49-8814-4379-b9bc-95a1ddce523d) • [8](https://biotanz.landcareresearch.co.nz/scientific-names/5957e956-2ef2-4da3-becf-7bf578e6f9f6) Other authorities keep the two names separate, with *C. rivulosa* described as having a more distinctly concentrically cracked cap surface, though these characters overlap extensively.[9](https://www.viriar.com/blogs/mushrooms-encyclopedia/clitocybe-rivulosa) Some guides suggest *C. rivulosa* is more common coastally and *C. dealbata* more inland, but this has not been molecularly confirmed, and the practical advice is to treat both identically.[10](https://www.out-grow.com/pages/ivory-funnel-clitocybe-dealbata) Catalogue of Life also lists the combination *[Collybia](https://www.edgepedia.org/collybia) dealbata* (Sowerby) Z.M.He & Zhu L.Yang among synonyms.[11](https://www.gbif.org/taxon/MTZVT)
## Description and habitat
The Ivory Funnel is a small white mushroom with a flatter, paler cap 2 to 5 cm across, growing in troops or rings in grassland.[5](https://www.coford.ie/media/coford/content/publications/ForestFungiinIreland2008160919.pdf) It is a grassland saprotroph that flushes after autumn rains, with troops and rings typically appearing roughly one to two weeks after a good soaking once temperatures have eased from summer highs; frost ends the season.[12](https://mushroomhunt.app/library/clitocybe-dealbata) The same mycelial ring expands outward slightly each year, so a marked patch returns reliably.[12](https://mushroomhunt.app/library/clitocybe-dealbata) Older accounts record that *C. dealbata* sometimes invades mushroom-beds.[13](https://rexresearch1.com/MushroomLibrary/MushroomsToadstoolsRamsbottom.pdf)
## Toxicity
Ingestion of *Clitocybe dealbata* results in an illness characterized primarily by profuse sweating, caused by high levels of muscarine, up to 0.15% of the mushroom.[4](https://www.fda.gov/files/food/published/Bad-Bug-Book-2nd-Edition-%28PDF%29.pdf) • [18](https://davidmoore.org.uk/21st_Century_Guidebook_to_Fungi_PLATINUM/REPRINT_collection/Michelot_etal_A.muscaria_chemistry_biology_toxicology.pdf) Muscarine activates receptors in the human nervous system and produces a cholinergic syndrome.[14](https://med.virginia.edu/brpc/wp-content/uploads/sites/274/2025/12/final-draft-reviewed-11-19-final.pdf) North American field-guide sources describe the species as poisonous and potentially fatal to children, with muscarine producing profuse sweating, salivation, and diarrhea.[15](https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Clitocybe+dealbata) The FDA's Bad Bug Book groups *Clitocybe dealbata* with *Inocybe* species such as *Inocybe geophylla* as the mushrooms responsible for this sweating type of neurological mushroom poisoning.[4](https://www.fda.gov/files/food/published/Bad-Bug-Book-2nd-Edition-%28PDF%29.pdf) At least four species of *Clitocybe*, including *C. dealbata* (then treated as *C. sudorifica*) and *C. rivulosa*, have been reported as containing muscarine or producing muscarine-like symptoms in humans.[16](https://rexresearch1.com/MushroomLibrary/PoisonousMushroomsNorthernUnitedStatesCanada.pdf)
## Lookalikes and identification
The most dangerous confusion is with edible grassland mushrooms that share the same habitat and rings. The Fairy Ring Champignon, *Marasmius oreades*, is similar in size and also forms rings on lawns, but has a tan or buff cap rather than a chalky white one, a low central bump, widely spaced pale gills that are free or barely attached rather than running down the stem, a tough pliant stem, and a sweet almondy smell.[12](https://mushroomhunt.app/library/clitocybe-dealbata) • [10](https://www.out-grow.com/pages/ivory-funnel-clitocybe-dealbata) The Miller, *[Clitopilus prunulus](https://www.edgepedia.org/clitopilus-prunulus)*, is somewhat similar but has pinkish spores and a farinaceous odor; field guides warn collectors to take great care separating it from *C. dealbata* and *C. rivulosa*, which are very similar in appearance and grow in similar places.[15](https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Clitocybe+dealbata) • [17](https://w.rexresearch1.com/MushroomLibrary/FieldGuideEdibleMushroomsBritainEuropeJordan.pdf) *Clitocybe candicans* differs in habitat and has more coarsely incrusted epicuticular hyphae.[15](https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Clitocybe+dealbata) Because some *Clitocybe* species are edible and all share the funnel form and decurrent gills, color, habitat, size, and odor alone are not reliable enough for safe identification without expert knowledge.[10](https://www.out-grow.com/pages/ivory-funnel-clitocybe-dealbata)
## Distribution and records
Databased records compiled by Biota of NZ include collections from Gisborne and Nelson in New Zealand and from the United Kingdom; the species carries a threat status of Data deficient in that database.[8](https://biotanz.landcareresearch.co.nz/scientific-names/5957e956-2ef2-4da3-becf-7bf578e6f9f6) In British Columbia the species is unlisted for conservation purposes.[15](https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Clitocybe+dealbata) Danish, French, and English common names are recorded, including Bleg tragthat, [Clitocybe](https://www.edgepedia.org/clitocybe) blanc-ivoire, Ivory Funnel, and Sweating Mushroom.[3](https://www.gbif.org/species/2531056)
## References
1. [Clitocybe dealbata (Sowerby) P. Kumm., Index Fungorum Name Record 216184, Royal Botanic Gardens Kew](https://www.indexfungorum.org/Names/namesrecord.asp?RecordId=216184)
2. [Clitocybe dealbata (Sowerby) P. Kumm., Species Dictionary, Natural History Museum, London](https://www.nhm.ac.uk/our-science/data/uk-species/taxon?tvk=NHMSYS0001477986)
3. [Clitocybe dealbata (Sowerby) P.Kumm., GBIF Backbone Taxonomy](https://www.gbif.org/species/2531056)
4. [Bad Bug Book, Handbook of Foodborne Pathogenic Microorganisms and Natural Toxins, 2nd Edition, U.S. Food and Drug Administration](https://www.fda.gov/files/food/published/Bad-Bug-Book-2nd-Edition-%28PDF%29.pdf)
5. [Forest Fungi in Ireland, COFORD](https://www.coford.ie/media/coford/content/publications/ForestFungiinIreland2008160919.pdf)
6. [NZOR Name Details: Clitocybe dealbata (Sowerby) P. Kumm.](https://nzor.org.nz/names/2bb94e49-8814-4379-b9bc-95a1ddce523d)
7. [Clitocybe rivulosa (= Clitocybe dealbata), Fool's Funnel mushroom, First Nature](https://www.first-nature.com/fungi/clitocybe-rivulosa.php)
8. [Clitocybe dealbata (Sowerby) P. Kumm. 1871, Biota of NZ, Manaaki Whenua Landcare Research](https://biotanz.landcareresearch.co.nz/scientific-names/5957e956-2ef2-4da3-becf-7bf578e6f9f6)
9. [Clitocybe rivulosa (Fool's Funnel), VIRIAR Mushrooms Encyclopedia](https://www.viriar.com/blogs/mushrooms-encyclopedia/clitocybe-rivulosa)
10. [Ivory Funnel (Clitocybe dealbata), Out Grow](https://www.out-grow.com/pages/ivory-funnel-clitocybe-dealbata)
11. [Clitocybe dealbata (Sowerby) P. Kumm., GBIF/Catalogue of Life](https://www.gbif.org/taxon/MTZVT)
12. [Ivory Funnel (Clitocybe dealbata), Mushroom Hunt library](https://mushroomhunt.app/library/clitocybe-dealbata)
13. [Mushrooms and Toadstools, Ramsbottom](https://rexresearch1.com/MushroomLibrary/MushroomsToadstoolsRamsbottom.pdf)
14. [Blue Ridge Poison Center guidance on Clitocybe muscarine poisoning, University of Virginia](https://med.virginia.edu/brpc/wp-content/uploads/sites/274/2025/12/final-draft-reviewed-11-19-final.pdf)
15. [E-Flora BC Atlas Page: Clitocybe dealbata](https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Clitocybe+dealbata)
16. [Poisonous Mushrooms of Northern United States and Canada](https://rexresearch1.com/MushroomLibrary/PoisonousMushroomsNorthernUnitedStatesCanada.pdf)
17. [Field Guide to Edible Mushrooms of Britain and Europe, Jordan](https://w.rexresearch1.com/MushroomLibrary/FieldGuideEdibleMushroomsBritainEuropeJordan.pdf)
18. [Michelot Etal A.muscaria Chemistry Biology Toxicology.pdf, davidmoore.org.uk](https://davidmoore.org.uk/21st_Century_Guidebook_to_Fungi_PLATINUM/REPRINT_collection/Michelot_etal_A.muscaria_chemistry_biology_toxicology.pdf)
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*Topic: Encyclopedia › Life and health › Microorganisms and fungi › Fungi and mycology › Basidiomycete taxa › Agaricomycetes › Agaricales › Tricholomataceae and allies › Clitocybe and allies*
*Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026; Oct 21, 2026 · Edited: Oct 11, 2026; Oct 15, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license