Poisonous

If someone may have eaten this mushroom, call Poison Control now, before symptoms start, and keep a piece of it for identification.

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What Is a Ghost Fungus? Illudin Toxins and the Tear Test

Omphalotus nidiformis · Family Omphalotaceae

By the KnowTheSpore teamPublished August 21, 20266 sources

Ghost fungus is famous for glowing green in the dark, yet the glow plays no part in the decision that poisons people. They make that decision in daylight, standing at the tree and wondering whether a pale cluster is an oyster mushroom. In daylight, check the cap, gills, stem, and attachment to wood.

Quick Facts

Cap: Fan- to funnel-shaped, up to about 30 cm across, cream through pale gray to smoky brown and often darker toward the center, with a wavy inrolled margin when young, growing in overlapping clusters.
Underside: Crowded, pale cream, and decurrent, running a long way down the stem rather than stopping at it. The gills are the part that glows.
Stem: Short and often off-center, sometimes almost absent, and tough and fibrous throughout rather than soft, which is the field mark that matters most.
Flesh & odor: Whitish, thin in the cap and toughening toward the base, with a faint unpleasant smell in older specimens.
Spore print: White to cream
Habitat: In overlapping clusters on the wood of living and dead trees, especially eucalypts, and on buried roots and stumps in sclerophyll woodland and gardens.
Season: Mainly autumn and early winter after rain, and it can appear at other times in wet years
Distribution: Southern Australia including New South Wales, Victoria, South Australia, Western Australia and Tasmania, with records extending into parts of Asia
Common names: Ghost fungus, ghost mushroom, Australian glowing mushroom
Type: Gilled

How do you tell it from an oyster mushroom?

The dangerous confusion is with oyster mushrooms. Royal Botanic Gardens Victoria records that people have mistaken ghost fungus for edible oysters, and it lists the species among the fungi known to cause poisonings in Victoria. The reason is structural, and careless picking does not explain it. Both grow in overlapping clusters on wood, both can be pale, and both have gills running down toward an off-center stem. Taxonomists once placed them in the same genus, so the resemblance is real.

The shapes overlap enough that shape alone will not settle it.

Color will not separate them either, because oyster mushrooms range from near-white through gray to tan and ghost fungus covers most of the same ground. Three features do the separating, and none of the three shows up in a photograph.

In daylight there is no glow at all, and this is what people actually photograph before asking what it is.

Oyster mushroomSoft flesh that tears cleanly, thin and even toward the base, faint sweet aniseed smell

Ghost fungusTough fibrous base that tears in strings, thickening toward the attachment, unpleasant smell when older

The first is the tear test at the base. Oyster flesh is soft and yields, while ghost fungus stays fibrous and stringy right through the point of attachment. The second is thickness. Oyster mushrooms stay comparatively thin and even in cross-section, while ghost fungus thickens noticeably as it nears the base.

The third is smell, which is soft evidence but still useful. Fresh oyster mushrooms smell faintly sweet and aniseed-like, and older ghost fungus develops a smell most people call unpleasant. If the cluster is on a eucalypt, take that as a reason for more care and never as proof either way. Oyster mushrooms do grow on eucalypts in Australia, so the host narrows the question without closing it.

Warning

Ghost fungus is poisonous. Laboratory analysis of cultured ghost fungus found the sesquiterpene toxins illudin S and illudin M, the same toxins as in North American jack o'lanterns. Because it carries the same illudins, eating it brings the nausea, vomiting, abdominal pain and sometimes diarrhea reported after jack o'lantern meals. In those poisonings, symptoms usually begin one to three hours after the meal and most people recover within about 12 hours. Severe vomiting can still drain enough fluid to need hospital treatment.

The speed is the one mercy here. Your mistake shows itself the same evening, while with the amatoxin mushrooms a delay of many hours is itself the danger. That contrast changes what a clinician needs to hear, because rapid onset points toward this kind of irritant poisoning and onset many hours after a meal points somewhere far more serious.

Anyone who has eaten a suspected ghost fungus should keep a piece of it, uncooked and unwashed if possible, and keep taking fluids. The specimen tells an identifier far more than any description could.

What does a ghost fungus look like in daylight?

Ghost fungus grows in overlapping clusters on wood, with fan- to funnel-shaped caps that can reach about 30 centimetres across. Large clusters on eucalypt stumps are among the more striking sights in an Australian wood. Its color varies too much to help you. Caps run from cream through pale gray to smoky brown, often darker toward the center and paler at the margin, and one cluster can show most of that range at once.

The gills stay constant where the color does not. They crowd together, pale and decurrent, which means they run a long way down the stem instead of stopping where the cap ends. You can both see that run and feel it. Draw a finger from the cap edge toward the base, and the gill ridges continue under your fingertip well past the point where a cap-and-stem mushroom would turn smooth.

The flesh is thin in the cap and grows tougher toward the base. By the point of attachment it feels closer to wood than to mushroom, and you can learn that change by hand. That same gradient is what the tear test at the base relies on.

How do you identify it without the glow?

Almost everything written about this mushroom leads with the glow, and in the field you cannot use it. Researchers have measured the glow as a real property of the species. Its purpose is still unclear, because one study tested the idea that it draws spore-carrying insects and found no support. Seeing it takes full darkness and eyes that have had ten or fifteen minutes to adapt. It is strongest in fresh mature specimens and fades with age, and a torch beam or a phone screen wipes it out completely.

Real, and photographed over a long exposure in total darkness, which is not the condition anyone identifies a mushroom in.

Nobody stands in a dark wood deciding whether to eat something. So identify ghost fungus as if the glow did not exist, using only what daylight shows.

GillsCrowded, pale, and running well down the stem rather than stopping at it

Stem textureTough and fibrous the whole way through, closer to wood than to mushroom flesh

GrowthOverlapping clusters on wood, including buried roots and stumps

HostEucalypts above all, in woodland and in gardens

Spore printWhite to cream, which does not separate it from an oyster mushroom

The stem texture is one of the more useful daylight checks, though no single character separates this pair on its own. It holds up in any light and any season, which the glow never does.

Gills that run down the stem, and a stem that stays tough all the way to the base.

Take hold of the base and try to tear it the way you would tear a piece of oyster mushroom. Ghost fungus resists, splits along fibres and feels stringy, and that result means you leave the cluster. Oyster mushrooms give way softly and tear cleanly, yet a clean tear on its own does not make a cluster an oyster. Do this before anything goes in a basket, because once you mix several clusters you have lost the chance to test each one at its base.

How do you tell ghost fungus from an oyster before picking?

Do not rely on the glow to clear a specimen either way. Fresh ghost fungus in a dark room may glow convincingly, while older specimens may show nothing at all. Darkness that produces no light has therefore told you nothing.

If vomiting starts within a few hours of a meal, seek medical advice and say what the person ate and when the illness started. Onset timing is the single most useful fact you can give a clinician. Rapid onset genuinely points away from the mushrooms that damage the liver.

Where does ghost fungus grow?

Ghost fungus is a wood decomposer, and it works on living trees as well as dead ones. It fruits in overlapping clusters at the base of trunks, on stumps and from buried roots, so clusters sometimes seem to grow out of bare ground with no wood in sight. Eucalypts are the usual host, which places the species in the woodland and the suburb at once.

Buried roots explain the clusters that seem to be growing from open ground.

Street trees, park plantings and garden stumps produce it as reliably as bushland does. That urban presence has a real consequence. Many people who meet this mushroom never set out to forage; they find something that appeared overnight in their garden.

Main seasonAutumn into early winter, following rain

Outside the windowA wet year can produce fruiting at other times

How long a cluster lastsAbout two weeks, darkening and drying as it ages

Onset if eatenUsually within a few hours of the meal, fast enough to connect meal and illness

The season runs mainly through autumn and into early winter after rain, though a wet year can bring fruiting outside that window. Clusters can grow large and last a couple of weeks, darkening and drying as they age.

Can cooking make it safe?

Ghost fungus has no culinary notes, and that gap is deliberate. Nobody has shown any cooking method to make it safe, so heat is never a reason to try it. Folk reasoning fails here as well. It is not bitter enough to warn you off, it does not look diseased, and young specimens can feel firm and pleasant in the hand.

Leave it where it grows. If you collect one specimen for identification, keep it well away from anything meant for a kitchen.

Does it turn up in cultivated beds?

Nobody cultivates ghost fungus for food, and there is no reason to. Laboratories grow it to study its glow, and one research group grows it in culture to produce illudin M, a lead compound in anticancer research. That is research work, and it has nothing to do with a home grower.

For a home grower the concern runs the other way, and it means making sure ghost fungus is not what came up in a wood-chip bed meant for an edible species. That does happen. Outdoor beds mulched with hardwood or eucalypt chips sit in exactly the habitat this fungus uses, so identify anything that appears in a bed and never assume.

Why was it once called an oyster mushroom?

The old name explains the modern problem. Ghost fungus once sat in Pleurotus, the oyster mushroom genus, a fair record of how alike the two look to a careful observer. It now belongs to Omphalotus, a genus known both for glowing and for being poisonous.

The genus name pays off because it repeats elsewhere. The jack-o-lantern mushrooms of North America and Europe are Omphalotus too, glow the same way, and get confused with chanterelles instead of oysters. So the pattern carries over even though the lookalike changes. Glowing mushrooms come from five separate lineages, Mycena species among them, so a glow alone does not prove an Omphalotus, and no Omphalotus is food.

Ghost fungus safety and identification questions

Is ghost fungus poisonous?

Yes, it is poisonous. It contains the sesquiterpenoid toxins illudin S and illudin M, which cause nausea, vomiting, abdominal pain and sometimes diarrhea. In jack o'lantern poisonings from the same toxins, symptoms usually begin one to three hours after the meal and clear within about 12 hours. It is not usually fatal, though severe vomiting can cause dehydration serious enough to need hospital treatment.

Does ghost fungus really glow?

Yes, and the gills are the part that glows greenish. Seeing it takes complete darkness and dark-adapted eyes. The glow is strongest in fresh mature specimens, fades with age, and vanishes under any torch or phone screen. It is real, yet useless at the moment anyone chooses whether to pick something.

How do you tell ghost fungus from an oyster mushroom?

Start with the base. Ghost fungus stays tough and fibrous right through the point of attachment and tears in strings, which means leave it, while an oyster mushroom is soft and gives way cleanly. Ghost fungus also thickens noticeably toward the base, where an oyster stays comparatively thin and even.

Can you cook ghost fungus to make it safe?

No. Nobody has shown any cooking method to remove its toxins, so no preparation makes it safe to eat.

Where does ghost fungus grow?

It grows in overlapping clusters on the wood of living and dead trees across southern Australia, most often on eucalypts, including street trees, park plantings and garden stumps. Clusters growing from buried roots can look as though they are coming out of bare ground.

When does ghost fungus fruit?

It fruits mainly in autumn and into early winter after rain, though a wet year can bring it outside that window. Each cluster can last a couple of weeks, darkening and drying as it ages.

Sources6

Edible and poisonous fungi, Royal Botanic Gardens Victoria Ghost fungus mistaken for edible oyster mushrooms and listed among the fungi known to cause poisonings in Victoria, and the warning that only a certain identification, not a folk test, shows whether a wild fungus is poisonous
Bioluminescence in the ghost fungus Omphalotus nidiformis does not attract potential spore dispersing insects, Fungal Biology 2016 That the bioluminescence is a measured phenomenon of this species and that its function is not settled, since the insect-attraction hypothesis was tested and not supported
Kirchmair, Pöder and Huber, Journal of Chromatography A 1999: Identification of illudins in Omphalotus nidiformis and Omphalotus olivascens var. indigo First detection of illudin M and illudin S in cultures of the Australian ghost fungus by liquid chromatography and tandem mass spectrometry.
Mushroom Poisoning Syndromes, North American Mycological Association Omphalotus poisoning from illudin M and illudin S: nausea, vomiting, abdominal pain and sometimes diarrhea one to three hours after the meal, most people recovered within 12 hours.
Perry, Desjardin and Stevani, Journal of Fungi 2024: Diversity, Distribution, and Evolution of Bioluminescent Fungi Bioluminescent mushrooms fall into five separate lineages, with Mycenaceae the largest.
Chaverra-Muñoz, Briem and Hüttel, Microbial Cell Factories 2022: Optimization of the production process for the anticancer lead compound illudin M Illudins as anticancer lead compounds, the illudin S derivative irofulven in phase II trials, and illudin M production by Omphalotus nidiformis in culture.

What Is a Ghost Fungus? Illudin Toxins and the Tear Test

Quick Facts

How do you tell it from an oyster mushroom?

What does a ghost fungus look like in daylight?

How do you identify it without the glow?

How do you tell ghost fungus from an oyster before picking?

Where does ghost fungus grow?

Can cooking make it safe?

Does it turn up in cultivated beds?

Why was it once called an oyster mushroom?

Ghost fungus safety and identification questions

Other mushrooms confused with oysters

Oyster Mushroom

Jack O'Lantern

Chanterelle

Shiitake