Omphalotus illudens

Omphalotus illudens, commonly known as the eastern jack-o'lantern mushroom, is a North American species of fungus.

Description

It forms a large, orange mushroom. The caps grow up to Template:Convert wide. The gills are decurrent and the stem is up to 15 cm long. The flesh is orange and the spore print is white to cream.<ref name="audu">Template:Cite book</ref>

Its gills often exhibit a weak green bioluminescence when fresh. This green glow has been mentioned in several journal articles, which state that the phenomenon can persist up to 40–50 hours after the mushroom has been picked.<ref>Template:Cite journal</ref><ref>Template:Cite book</ref> It is believed that this display serves to attract insects to the mushroom's gills at night, which can then distribute its spores across a wider area.<ref>Template:Cite journal</ref>

Similar species

Omphalotus lludens is replaced by O. subilludens on the Gulf Coast, and O. olivascens is found in California.<ref name="audu" /> Desarmillaria tabescens forms small, dull orange caps.<ref name="audu" />

Omphalotus illudens is sometimes confused with edible chanterelles, but can be distinguished by its thicker, fleshier appearance, tendency to form large clusters, and clearly separated caps when young. Unlike chanterelles, O. illudens is poisonous to humans when eaten, whether raw or cooked. Although some older literature claims the name is synonymous with O. olearius, phylogenetic analysis confirms the two as distinct species.<ref name="Kirchmair2004" />

Habitat and distribution

Omphalotus illudens is often found in clumps on decaying stumps, buried roots, or at the base of hardwood trees in eastern North America (June–November).<ref name="audu" />

Toxicity

The poisonous chemical compounds illudin S and illudin M were isolated from O. illudens.<ref name="Anchel 1950">Template:Cite journal</ref><ref>Template:Cite journal</ref> In addition to their antibacterial and antifungal effects, illudins appear to be the cause of human toxicity when these mushrooms are eaten raw or cooked, causing vomiting, cramps, and diarrhea. Muscarine has also been indirectly implicated in toxicity,<ref name=Clark1913/> but modern studies to demonstrate its presence in O. illudens are needed.

The cytotoxic effect of illudin is of interest for treating some cancers, but illudin itself is too poisonous to use directly so it must first be chemically modified. Inside human cells, illudin S reacts with DNA and creates a type of DNA damage that blocks transcription. This block can only be relieved by a repair system called nucleotide excision repair. Damage in non-transcribed DNA areas is left unrepaired by the cell. This property was exploited by the company MGI Pharma to develop an illudin-derivative called Irofulven for use as a cancer treatment. Its application is still in the experimental phase.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Gallery

• Close-up
  Close-up
• Underside
  Underside
• Cluster with U.S. quarter for size reference
  Cluster with U.S. quarter for size reference
• Displaying bioluminescence
  Displaying bioluminescence
• In light and darkness
  In light and darkness
• Clusters growing at the base of an oak tree
  Clusters growing at the base of an oak tree
• Growing near trunk
  Growing near trunk
• Specimens
  Specimens
• Clusters
  Clusters

See also

• List of bioluminescent fungi