Omphalotus olivascens | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Basidiomycota |
Class: | Agaricomycetes |
Order: | Agaricales |
Family: | Omphalotaceae |
Genus: | Omphalotus |
Species: | O. olivascens |
Binomial name | |
Omphalotus olivascens | |
Omphalotus olivascens | |
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![]() | Gills on hymenium |
![]() | Cap is infundibuliform |
![]() | Hymenium is decurrent |
![]() | Stipe is bare |
![]() | Spore print is yellow |
![]() | Ecology is saprotrophic |
![]() | Edibility is poisonous |
Omphalotus olivascens, commonly known as the western jack-o'-lantern mushroom, [1] is an orange to brown-colored gilled poisonous mushroom endemic to the North American west coast. It has several lookalikes including Cantharellus cibarius .
The fungus was described as new to science in 1976 by American mycologists Howard E. Bigelow, Orson K. Miller Jr., and Harry D. Thiers. [2] A subspecies with blue flesh, O. olivascens var. indigo, was described growing on live oak in Baja California, Mexico. [3]
The cap is 4–18 cm (1.6–7.1 in) wide. The stalks are 4–15 cm (1.6–5.9 in) long and 1–4 cm (0.39–1.57 in) wide. The spores are white to pale yellow. [4]
To an untrained eye, O. olivascens appears similar to Cantharellus cibarius , [1] but the jack-o'-lantern mushroom has true, blade-like [5] gills (rather than ridges) and it can have olive coloration that chanterelles lack; also, Omphalotus species are saprotrophic, grow directly on wood, and are bioluminescent. [6]
Several Omphalotus species with similar bioluminescent properties occur worldwide, all of which are presumed poisonous. The best known are the North American jack o'lantern mushroom ( O. olearius ) and the tsukiyotake ( O. japonicus (Kawam.) Kirchm. & O.K. Mill. (formerly known as Lampteromyces japonicus (Kawam.) Sing.), found in Japan and eastern Asia. Molecular analysis shows the jack-o'-lantern to be most closely related to the ghost fungus O. nidiformis, [7] the colours and shades of which most closely resemble O. olivascens. [8] Additionally, O. illudens is similar. [9]
Gymnopilus junonius is another similar-looking species. [4]
It is endemic to the North American west coast, [1] namely the California Floristic Province.[ citation needed ]
A saprobe or parasite, O. olivascens is usually found on oak or Eucalyptus , [9] rarely on other hosts.
Omphalotus species cause a white rot by breaking down lignin in their tree hosts. [7]
The jack o'lantern mushroom is poisonous; while not lethal, consuming this mushroom leads to very severe cramps, vomiting, and diarrhea. [6]
The toxic ingredient of many species of Omphalotus is a sesquiterpene compound known as illudin S. [10] This, along with illudin M, have been identified in O. nidiformis. The two illudins are common to the genus Omphalotus and not found in any other basidiomycete mushroom. [11]