Did you know that some mushrooms glow in the dark? If that fact excites you, buckle up ’cause we’re diving into the amazing, glowing world of jack-o’lantern mushrooms. As a look-a-like to edible chanterelles, it’s a good idea to know how to identify these beautiful but poisonous mushrooms.
This guide will cover their fungal classification, where they grow, and what makes them poisonous. We’ll also explore what makes them glow and how they compare to some species of chanterelles.
So, without further ado, let’s dive in!
Jack-o’Lantern Mushrooms: Fungal Classification
Jack-o’lantern mushrooms belong to the Marasmiaceae family. Mushrooms in this family have a cap and stipe structure, are saprobic (meaning they derive nutrients from decaying organic matter), and grow in clusters near their host trees/logs. These glowing mushrooms belong to the Omphalotus genus, with a few species sharing the common name “jack-o’-lantern mushroom”. These species are Omphalotus illudens, Omphalotus olearius, and Omphalotus olivascens. In this guide, we’ll talk in-depth about the eastern North American species, Omphalotus illudens.
How to Identify Them
Gorgeous in the day and night, these lovely mushrooms are generally easy to identify once you know some specific features to look for.
Look For a Bright Orange Cluster
As their name suggests, jack-o’lantern mushrooms are bright orange (like a Halloween pumpkin). Generally, the caps display the brightest orange, followed by the gills, with pale orange stripes. Suppose you’re wandering through the forest of Eastern North America in the early Fall and come across a strikingly orange, dense cluster of mushrooms growing from rotting wood. In that case, it’s very possible you’ve found a flush of Omphalotus illudens.
Check Out the Gills
The gills on these mushrooms are bright to pale orange and quite noticeable. Rather than ending where the stipe begins, the gills run from underneath the cap down the upper portion of the stipe (decurrent). This gives the upper part of jack-o’lantern mushroom stipes a striped appearance. The gills are closed or crowded.
If you take a spore print by cutting off the cap and placing it gill-side-down on a dark sheet of paper for a couple of hours, the spore print should look creamy white to pale yellow.
Look at the Cap
The cap of Omphalotus illudens starts out convex with rolled-in margins and a bump centered over the stipe. When young, the cap is generally uniformly shaped and centered over the stipe. As it matures, the cap flattens outward and eventually turns into a v-shape with upturned margins. When mature, the shape of the cap is often much more irregular and lobed along the margins. When fully mature, the cap can reach 8 inches across.
Note the Stipe
As mentioned above, the stipe is typically the palest structure on jack-o’lantern mushrooms. When mature, it reaches between 3-5 inches long and tapers down to the base. This tapering-down feature is much more apparent in mature specimens.
Cut It Open
When cut open, the flesh should be pale orange, and the color should remain unchanged by bruising or oxygen exposure. The inside of the mushrooms should be firm and fleshy.
Where Do They Grow?
The Omphalotus illudens species of these spooky mushrooms grows widely across the woodlands of Eastern North America.
These mushrooms are saprobic, meaning they derive their nutrients from decaying organic matter. In their case, this matter is decaying wood that they help decompose.
While you’ll often see clusters of jack-o’lanterns growing on a rotting stump or log, you may also think they’re growing from the soil. However, clusters that appear to be fruiting from the soil are actually growing from rotting wood underneath the soil or leaf litter.
How and Why Jack-O’Lantern Mushrooms Glow in the Dark
One of the coolest aspects of jack-o’lantern mushrooms is that they glow in the dark! This is known as bioluminescence and is found in some plants, fungi, and even animals (like the firefly squid!). If you find a cluster of jack-o’lanterns at night and are lucky enough to be out in the woods away from artificial light sources, you should see the gills glow a soft, eerie pale green. Typically, the glow is brightest on young specimens.
Until recently, scientists weren’t sure how mushrooms got their bioluminescence. However, in 2017 an international team of researchers discovered that the glow of due to a reaction between luciferin molecules and the luciferase enzyme when in the presence of oxygen.
Interestingly, the role of bioluminescence in mushrooms is likely to attract insects at night to contact its spore-releasing tissue and disperse the spores when they fly away.
Are Jack-O’Lanterns Poisonous?
Regarding human ingestion, jack-o’lantern mushrooms are poisonous but not deadly. The toxin produced by jack-o’-lantern mushrooms is called illudin S.
Ingestion of this toxin typically leads to severe stomach cramps, vomiting, and diarrhea. The toxin is absorbed quickly by the body, so symptoms can appear as little as 20 minutes after ingestion. However, symptoms may also not start up to four hours after ingestion. Symptoms usually resolve within 24 hours and may require supportive care from a hospital, such as intravenous fluids, to prevent or treat dehydration.
Jack-O’Lantern Mushrooms’ Edible Look-Alikes: Chanterelles
Most poisoning from O. illudens happens when beginner foragers mistake them for yellow-orange chanterelles that grow in Eastern North America. When foraging for chanterelles, it’s important to note the differences between them and jack-o’lanterns, as they can grow in similar places around the same time.
Some chanterelle species that share growing regions with O. illudens include the Cantharellus lateritius, Cantharellus confluens, Cantharellus minor, and Cantharellus persicinus species. All of these chanterelle species grow East of the Rocky Mountains and may flush at the same time as jack-o’lantern mushrooms.
Firstly, chanterelles are mycorrhizal (form a beneficial fungi-plant relationship to gain nutrients) rather than saprobic, so you will not see them growing from decaying wood like jack-o’lanterns. They will instead grow from the soil near the trees they have mycorrhizal relationships with, as they derive nutrients from the tree’s roots. If you’re unsure if the mushroom is growing from the soil or wood beneath soil or leaf litter, gently brush around and beneath it to see if it’s actually growing from wood.
Secondly, chanterelles have false gills rather than true gills. This means rather than gills; they have forked wrinkles underneath the cap, which are less deep than true gills and can not be separated or moved when brushed. False gills should be firm to the touch and can not easily be separated from the mushroom.
Finally, most chanterelle species have a sweet, fruity aroma resembling an apricot or peach. Jack-O’Lantern mushrooms do not have this distinctive odor.
Can You Grow Jack-O’Lantern Mushrooms?
If you want to enjoy the bright colors and spooky glow of jack-o’lantern mushrooms, you’ll be pleased to know you can grow them if you live in the correct region. Since these mushrooms aren’t mycorrhizal, they grow easily when inoculated on the right logs, such as oak and beech trees.
Potential Medicinal Properties of Jack-O’Lantern Mushrooms
So, you might think that since mushrooms are poisonous to eat, they don’t have medicinal potential. However, jack-o’lantern mushrooms are one of the top producers of the chemical, lovastatin, which doctors use to lower cholesterol and prevent heart disease.
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The photo featured at the top of this post is © John_P_Anderson/Shutterstock.com
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- Messiah, Available here: https://www.messiah.edu/Oakes/fungi_on_wood/gilled%20fungi/species%20pages/Omphalotus%20illudens.htm
- AZ Animals, Available here: https://a-z-animals.com/blog/10-animals-that-glow-in-the-dark/
- PubMed, Available here: https://pubmed.ncbi.nlm.nih.gov/2024797/