Fungus · GBIF taxon 3321446
western jack-o'-lantern
Omphalotus olivascensAlso known as Western Jack-O'-Lantern Mushroom
Western jack-o'-lantern mushrooms fruit in dense clusters around the bases of hardwood trees and submerged decaying roots along the Pacific coast. They feature olive-tinted orange caps and sharp, decurrent gills that emit a faint green bioluminescent glow in total darkness. As a saprobic fungus, this species plays an important role in breaking down dead oak and eucalyptus wood across its native range.
BioluminescentToxicFungus
—observations
—countries
—peak records
Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Diet & prey
- Decaying Hardwood
- Organic Matter
Predators
- Fungus Gnats
- Slugs
- Beetles
ThreatsHabitat loss and removal of mature host trees
HabitatsOak woodlands, mixed hardwood forests, coastal valleys
Life spanFruiting bodies last 1–2 weeks; mycelium lives perennially
Size / weightNot available
Classification
- FamilyOmphalotaceae
- SpeciesOmphalotus olivascens
Range data is not available yet.
Interaction riskHigh
- Low
- Moderate
- High
- Very high
- Why interaction risk is high
- Contains severe gastrointestinal toxins and has look-alikes; never eat wild fungi based on app identification alone.
- Why it is dangerous
- Contains illudin toxins that induce severe vomiting, stomach cramps, and extreme nausea within hours of ingestion.
- How to recognize a risky encounter
- Recognized by dense clumping growth at tree bases, olive-orange caps, and deep decurrent gills.
- What to do
- Do not harvest or consume; admire and photograph from a safe distance.
Responsible observation
- Nighttime Viewing: Observe fresh clusters in absolute darkness to spot faint green gill glow.
- Safe Identification: Examine the true decurrent gills running down the stem to distinguish from chanterelles.
- Leave in Place: Photograph mushrooms where they grow without disturbing the substrate.
Dangerous Look-Alike (c) Alan Rockefeller, some rights reserved (CC BY), uploaded by Alan Rockefeller · cc-by
Host Tree no rights reserved, uploaded by Anne Parsons · cc0
Close Relative (c) Jason Hollinger, some rights reserved (CC BY) · cc-by
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