Psilocybe fimetaria

Psilocybe fimetaria
Scientific classification
Kingdom:	Fungi
Division:	Basidiomycota
Class:	Agaricomycetes
Order:	Agaricales
Family:	Hymenogastraceae
Genus:	Psilocybe
Species:	P. fimetaria
Binomial name
Psilocybe fimetaria (P.D. Orton) Watling (1967)
Synonyms [1]
Stropharia fimetariaP.D.Orton (1964)

Psilocybe fimetaria
Mycological characteristics
	Gills on hymenium
	Cap is convex or umbonate
	Hymenium is adnexed or free
	Stipe has a cortina
	Spore print is blackish-brown to purple
	Ecology is saprotrophic
	Edibility is psychoactive

Psilocybe fimetaria is a dung-loving mushroom, usually found on horse dung. ^{[2] [3]} Along with Psilocybe fuscofulva , it is one of two Psilocybe mushroom species that has been found to contain no detectable levels of the psychoactive tryptamines psilocin, psilocybin, or others. In the case of P. fimetaria, this may be due to some individual specimens having a very low concentration, or the species actually being a pair of morphologically similar species. ^{[4] [5]}

Etymology

• From the Latin word 'fĭmus', meaning dung, excretement or manure, and the standard Latin suffix '-arius', meaning engaged-in or structured. ^[6]

Description

• Cap: 0.5 — 3.5 cm in diameter, papillate to convex, becoming umbonate to broadly convex in age. Surface even to translucent-striate near the margin, viscid when moist from a thick separable gelatinous pellicle. Often velar remnants on surface, typically around the margin. Pale reddish brown to ochraceous, hygrophanous, fading in drying to yellowish olive to ochraceous buff. Flesh whitish to honey colored.
• Gills: Adnexed, free or sinuate. Close, interleaving and ventricose. Whitish clay at first, eventually dark reddish brown with olivaceous hue, white fimbriate.
• Spore Print: Dark purple-brown, (9.5)12.5 — 15(16) x 6.5 — 9.5 μm, ovoid in front view, ellipsoid in side view, thick walled with a broad germ pore.
• Stipe: 2 – 9 cm long by (0.5)2 – 4 mm thick. Cylindrical, flexuous, equal but sometimes slightly swollen at the base. Whitish at first, soon discolouring yellow to yellowish brown from handling, reddish brown or honey brown in age, sometimes with distinctive blue tones at the base. Surface covered with whitish fibrils towards the apex, with an apical evanescent fibrillose annulus that develops from a thickly cortinate partial veil.
• Odor: Farinaceous
• Taste: Farinaceous
• Microscopic features: Basidia 4-spored. Pleurocystidia absent. Cheilocystidia (15)20 — 30(35) by (4)6 — 8(9) μm, ventricose-fusiform or lageniform with a narrow neck, often flexuous, 4 — 15 by 0.5 — 1.5 μm, occasionally branched.

The gills of P. fimetaria are adnexed or freely attached, curving up before meeting the top of the stem

Habitat and distribution

P. fimetaria is found growing solitary or in small groups on horse or cow dung, in grassy areas, in Autumn from September to November. ^{[3] [2]} The species is generally uncommon and infrequently recorded, but it can occasionally occur in large numbers in localized areas. ^[2] Psilocybe semilanceata may be an indicator species for P. fimetaria, as they both favour similar grasses, soil types and climatic conditions. It is widely distributed but not very common.

It has been recorded in Great Britain, Iceland and much of mainland Europe. ^{[2] [3]} Despite what much of the literature states, there have not been confirmed recordings of P. fimetaria in Asia or the Americas (Canada, the Pacific Northwest and Chile). ^{[3] [7] [8]} However, Paul Stamets suggests that the actual range in which these mushrooms fruit is likely much wider than what has been documented so far. ^[5]

Similar species

P. fimetaria is phylogenetically a close relative of Psilocybe liniformans . Not only do they often grow in the same habitat, but they are macroscopically similar. The best way to differentiate the species by testing for the presence of separable gelatinous threads running along the bottom edge of the gills. This feature would indicate P. liniformans.

Deconica coprophila can also appear similar but can be distinguished by its adnate or subdecurrent gill attachment, less-dense gill spacing and its cap being a deeper red colour.

Gallery

• 
  P. fimetaria at various stages of development
• 
  Two P. fimetaria on dung amongst heather
• 
  Single P.fimetaria with sharp papilla
• 
  Two P. fimetaria with Panaeolus papilionaceus behind
• 
  P. fimetaria spores 1000x

References

1. "GSD Species Synonymy: Psilocybe fimetaria (P.D. Orton) Watling". Species Fungorum. CAB International. Retrieved 2014-11-30.
2. Buczacki, Stefan; Shields, Chris; Ovenden, Denys (2012). Collins Fungi Guide: The most complete field guide to the mushrooms & toadstools of Britain & Ireland. London: HarperCollins Publ. ISBN   978-0-00-746648-1.
3. Stamets, Paul (2023). Psilocybin Mushrooms of the World: An Identification Guide. Andrew Weil. New York: Potter/Ten Speed/Harmony/Rodale. ISBN   978-1-60774-199-2.
4. Gotvaldová, Klára; Borovička, Jan; Hájková, Kateřina; Cihlářová, Petra; Rockefeller, Alan; Kuchař, Martin (2022). "Extensive Collection of Psychotropic Mushrooms with Determination of Their Tryptamine Alkaloids". International Journal of Molecular Sciences. 23 (22) 14068. doi: 10.3390/ijms232214068 . PMC   9693126 . PMID   36430546.
5. Stamets, Paul (2025). Psilocybin Mushrooms in Their Natural Habitats A Guide to the History, Identification, and Use of Psychoactive Fungi. New York: Ten Speed. pp. 160–161. ISBN   9781984863034.
6. Olivetti, Olivetti Media Communication-Enrico. "ONLINE LATIN DICTIONARY - Latin - English". online-latin-dictionary.com. Retrieved 2026-01-23.
7. "Psilocybe fimetaria (P.D.Orton) Watling". www.gbif.org. Retrieved 2026-01-23.
8. "Psilocybe fimetaria". iNaturalist. Retrieved 2026-01-23.

External links

• Psilocybe fimetaria image
• Psilocybe fimetaria image