Gymnopilus junonius

Gymnopilus junonius is a species of mushroom-forming fungus in the family Hymenogastraceae. Commonly known as the spectacular rustgill, this large orange mushroom is typically found growing on tree stumps, logs, or tree bases. Some subspecies of this mushroom contain the neurotoxic oligoisoprenoid gymnopilin.

Gymnopilus junonius
Gymnopilus junonius-02.jpg
Scientific classification edit
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Hymenogastraceae
Genus: Gymnopilus
G. junonius
Binomial name
Gymnopilus junonius
(Fr.) P.D.Orton (1960)
Gymnopilus junonius.png
Approximate range of Gymnopilus junonius
  • Agaricus aureus Bull. (1782)
  • Agaricus junonius Fr. (1821)
  • Lepiota aurea Gray (1821)
  • Pholiota junonia (Fr.) P.Karst. (1879)
  • Pholiota grandis Rea (1903)
  • Pholiota spectabilis var. junonia (Fr.) J.E.Lange (1940)
  • Gymnopilus spectabilis var. junonius (Fr.) Kühner & Romagn. (1953)
Gymnopilus junonius
View the Mycomorphbox template that generates the following list
gills on hymenium
cap is convex
hymenium is adnate
stipe has a ring
spore print is reddish-brown
ecology is saprotrophic
edibility: inedible


The cap ranges from 8–30 cm (3–12 in) across, is convex to flat,[1] and is bright yellow-orange in younger specimens and orange-brown or reddish brown in older ones, with a dry scaly surface. The flesh is yellow, the odor mild and taste bitter.[1] The stem is 5–25 cm (2–10 in) long, 1–5 cm thick, and often narrows near the base.[1] The frail ring is dusted with rusty orange spores, and the gill attachment to the stem is adnate to sub-decurrent.[1] It stains red with KOH and turns green when cooked. The spore print is rusty orange. Unlike psychoactive relatives in the Psilocybe genus, G. junonius lacks psilocybin and does not stain blue, but smaller specimens occasionally exhibit bruising.[2] This mushroom usually grows in clusters from several to several dozen individuals, but sometimes grows solitary. It is inedible due to its bitter taste.

Gymnopilus junonius

Similar speciesEdit

This mushroom is often mistaken for Gymnopilus ventricosus, which also contains no psilocybin and G. luteus and G. subspectabilis, which do.[citation needed] It also resembles Armillaria mellea and Omphalotus olivascens.[1]

Distribution and habitatEdit

Gymnopilus junonius is found in Europe, Australasia and South America.[3][4][5] It grows in dense clusters on stumps and logs of hardwoods and conifers. This mushroom is most common in moist, lowland wooded areas near rivers.

This species does not occur in North America; however some similar looking species do. These include Gymnopilus ventricosus on the west coast and G. luteus and G. subspectabilis in the midwest and east.[6]


This mushroom contains bis-noryangonin and hispidin, which are structurally related to alpha-pyrones found in kava.[7] Neurotoxins known as oligoisoprenoids have also been found in this species.[8]

See alsoEdit


  1. ^ a b c d e Davis, R. Michael; Sommer, Robert; Menge, John A. (2012). Field Guide to Mushrooms of Western North America. Berkeley: University of California Press. pp. 245–246. ISBN 978-0-520-95360-4. OCLC 797915861.
  2. ^ Thorn, R. Greg; Malloch, David W.; Saar, Irja; Lamoureux, Yves; Nagasawa, Eiji; Redhead, Scott A.; Margaritescu, Simona; Moncalvo, Jean-Marc (2020-04-24). "New species in the Gymnopilus junonius group (Basidiomycota: Agaricales)". Botany. Canadian Science Publishing. 98 (6): 293–315. doi:10.1139/cjb-2020-0006. ISSN 1916-2790.
  3. ^ "Big Laughing Jim/Scientific Name: Gymnopilus junonius (formerly G. spectabilis)". Missouri Department of Conservation ( Archived from the original on 2021-01-04. Retrieved 2020-09-27.
  4. ^ "Earth Notes: The Laughing Jim Mushroom". Archived from the original on 2021-01-04. Retrieved 2020-09-27.
  5. ^ "Gymnopilus junonius (Fr.) P. D. Orton - Spectacular Rustgill". Archived from the original on 2021-01-04. Retrieved 2020-09-27.
  6. ^ "New species in the Gymnopilus junonius group (Basidiomycota: Agaricales)" (PDF). Retrieved 2022-03-28.{{cite web}}: CS1 maint: url-status (link)
  7. ^ Hatfield, G.M.; Brady, L.R. (1969). "Occurrence of bis-noryangonin in Gymnopilus spectabilis". Journal of Pharmaceutical Sciences. 58 (10): 1298–1299. doi:10.1002/jps.2600581039. PMID 5388695.
  8. ^ Tanaka, Masayasu; Hashimoto, Kimiko; Okunoa, Toshikatsu; Shirahama, Haruhisa (1993). "Neurotoxic oligoisoprenoids of the hallucinogenic mushroom, Gymnopilus spectabilis". Phytochemistry. 34 (3): 661–664. doi:10.1016/0031-9422(93)85335-O.
  • C.J. Alexopolous, Charles W. Mims, M. Blackwell et al., Introductory Mycology, 4th ed. (John Wiley and Sons, Hoboken NJ, 2004) ISBN 0-471-52229-5

External linksEdit