Omphalotus olivascens

Today, we feature this once-in-a-lifetime shot of a glowing-in-the-dark Omphalotus olivascens captured by Damon Tighe (aka Damon Tighe@Flickr) in Mt. Diablo State Park, California, USA. I had no idea that phosphorescent fungi existed, and suspected Damon of photoshopping the glow onto this image, but it turns out the photo is legitimate. Once again I am astounded at the diversity of the botanical world (sorry to have doubted you, Damon!).

Omphalotus olivascens, or the Western jack-o-lantern fungus, earns its common name from the phosphorescent enzyme that is secreted from its gills. This enzyme makes the fruiting fungus glow in the dark. The fruiting period coincides with Hallowe’en, but the Western jack-o-lantern is all trick and no treat. The mushroom smells delicious, and looks quite similar to a chanterelle (Cantherellus spp.), but when ingested will result in multiple days of diarrhea and vomiting–a tummy ache worse even than the one my 5 year-old had the year that he decided to eat most of his Hallowe’en treats in one sitting.

Although Omphalotus olivascens is found abundantly in north-central California, I could not find information about its exact entire range. It is often described as a western North American species, and on the east coast of North America the very similar Omphalotus olearius can be found. The western species of jack-o-lantern fungus has a brownish-orange to olive coloured cap and large spores, while the eastern species is bright orange and has smaller spores. Botany Photo of the Day published a great write-up about the eastern Omphalotus olearius in 2009, which explains in more detail the phenomenon of phosphorescence found in both of these species of Omphalotus.

Moselio and Elio Schaechter, in In the Company of Mushrooms: A Biologist’s Tale, shed more light (haha) on the topic of fungal phosphorescence. According to the Schaechters, the greenish glow emitted by Omphalotus species is called “foxfire”, and is found not only on the mushroom’s gills, but also in the fungus’ mycelium. Rotting wood full of such mycelium can be seen to glow for a couple of weeks, and this “touchwood” has a rich cultural history. The Schaechters describe it as having been used by native American shamans, lost Scandinavians, World War 1 soldiers, and maybe even Moses, for lighting and night-time wayfinding.

Omphalotus olivascens

9 responses to “Omphalotus olivascens”

  1. Mike Christison

    Wow! Spectacular photo!

  2. MollymCA

    Humph, I never caught one glowing! So I went to Damon Tighe’s Flickr site, found the photo, and looked at the EXIF which tells everything I wanted to know about how the shot was got — and more. Thanks for being so generous with the data, Damon! I was especially interested to see that you’ve conquered GIMP (open-source answer to Photoshop) now that Adobe has decided we should all rent Cloudware rather than having new versions at our disposal on our hard drives.
    I was kind of surprised to see the location as Diablo’s not far from me and it’s been so dry that the only mushrooms I saw all winter here were in places that got a bit of our well water somehow.

  3. Bonnie

    Very cool!

  4. Damon Tighe

    Thanks Tamara for picking this image up! As MollymCA eluded to the image was not an easy capture (ISO 1600 @ 30 seconds). To further round out the story; I took the fungi home and into a dark room where I popped them up for the exposure and then used GIMP to darken the image edges and soft focus the fungi. I’ve known this species glows for years, but this was the first time I’ve actually taken ones home that had enough glow to photograph. It has been a dry year, but the waterfall trail on Diablo does a great job at capturing moisture so In February you can consistently see 10-20 species of fungi on the loop trail. Here is what else was up that day so you have a feel for it.
    for those you looking to get out and see them, they tend to re-occur for a a few years in the same area until their substrate is gone and if you click on the map here in iNaturalist you can find exactly where they are and when they were fruiting:

  5. LXR

    In Australia, one of our luminescent fungi is Omphalotus nidiformis. July is a good time to look for them, especially on the Western Australian weeping peppermint Agonis flexuosa. They grow on a part of the trunk which has been damaged previously. To my eyes, the luminescence appears pale blue but the photos I have seen show a green glow.

  6. Bill Barnes

    there are a number of phosphorescent fungi on rotted wood here in the East Coast , very intriguing when you first see it . AS per the name , foxfire , remember the series of down home traditions and folklore from the late 70’s labeled Foxfire . The origin of the book titles is from the fungi at night .

  7. Ray Collier

    A few years ago during grad school at WSU in Pullman, Washington, my wife and I were lucky enough to enjoy a lecture/show put on by Taylor Lockwood, perhaps one of the most enthusiastic mycophiles on Earth. His Web page has numerous examples of bioluminescent fungi. The link is:

  8. Marian Whitcomb

    I am ashamed to admit to having a few too many one night whilst camping in North Florida. What started as rum and coke devolved into rum and ginger-ale, then rum and orange soda, and finally rum and grape soda. Upon running out of mixer, we decided to retire. We were trying to put out our campfire safely and stamping out all the little embers everywhere (sans rational function). We stamped and stamped. It seemed like it took forever. Finally I looked at him, he looked at me, and then we looked for the campsite, which was rather far up the hill in the distance from where we were standing! I realized we were stamping out phosphorescent fungi. Not one of my better moments, but seemed fun to share. Doing penance by trying to educate very skeptical folks in a very rural area about invasive plants, LOL.

  9. michael aman

    Last July we were collecting chanterelles (Upstate New York) when we came upon something of the same yellow color and general shape. But much more lush, growing in a colony of 7 or 8 fruiting bodies instead of singly, and larger. We took one home to try to identify and left it on the kitchen table. Later on, we went into the kitchen without turning on the light and were amazed at the luminescence.

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