Poison Red Mushroom ID: Fly Agaric, Sickener and More

The best-known poisonous red mushroom is the fly agaric, but colour alone sorts nothing. The pages that rank for this search list ox tongue, lobster mushroom, Caesar's mushroom, reishi, fly agaric and the deadly poison fire coral side by side, all of them red or red-orange (Zombie Myco; Real Mushrooms). Poison Control's position is that unless you are very experienced in mushroom identification, you cannot tell poisonous from edible species.

So the useful questions are about structure, not colour:

• Gills or pores? Red caps with gills include the fly agaric and the sickener; red pores point to boletes.
• What is at the base? A bulb with rings of scales points to Amanita.
• Does it change colour when cut or pressed? Some red-pored boletes turn blue at once.
• What is it growing on? Soil under trees, mulch, or wood.
• Is it even a cap? A red lattice or a red finger-like coral is a different kind of fungus altogether.

The fly agaric, Amanita muscaria, is the red mushroom of fairy tales: a bright red cap dotted with white warts, white gills, a white stem with a ring, and a bulbous base. Wikipedia notes two changes that trip people up: the colour ranges from red to orange and yellow and fades with age and rain, and the warts wash off in rain, so an older cap can be plain red or orange.

Its closest lookalike is Caesar's mushroom, Amanita caesarea, which Wikipedia separates by its entirely orange to red cap without the white warts, and its yellow gills, stem and ring instead of white ones. Both are Amanitas, the genus that also contains the death cap, so this is a comparison for recognition, not for picking. Full details on fly agaric.

Fly agaric contains ibotenic acid, which the body converts to muscimol. Wikipedia reports that effects begin around 30 to 90 minutes after eating and peak within three hours, although some last for days. They range from nausea to delirium, with distorted sight and hearing, mood changes, loss of coordination and loss of balance.

Wikipedia cites the North American Mycological Association as finding no reliably documented deaths from its toxins in the past 100 years. That does not make it harmless: it is a serious poisoning, children are smaller, and the same genus contains the deadliest mushrooms in the world. If anyone has eaten a red mushroom, call Poison Control at 1-800-222-1222 (U.S.) now.

Dogs eat it too. NAMA notes that Amanita muscaria is frequently eaten by dogs, possibly because of a fishy smell, and describes a deep coma-like sleep beginning a few hours after eating, with recovery generally around 6 hours later but sometimes as long as 72 hours. Call your vet or ASPCA Animal Poison Control at (888) 426-4435.

The sickener, Russula emetica, is a red mushroom with white gills and no warts. Wikipedia describes:

• Cap: bright scarlet or cherry red, 2.5 to 10 cm wide, with fine radial grooves near the edge.
• Gills: white to creamy white, closely spaced.
• Stem: white, 4.5 to 10.5 cm long, smooth.
• Spore print: white to yellowish white.
• Where: with conifers, especially pines, and in sphagnum moss near bogs.
• If eaten: nausea, vomiting, diarrhoea and cramps starting half an hour to three hours later.

Field guides describe the raw flesh as extremely peppery. This site does not recommend tasting any unknown mushroom. Several other red Russulas look similar, including the beechwood sickener (Russula nobilis) and the bloody brittlegill (Russula sanguinaria), and telling them apart takes expert work.

Some are. Satan's bolete, Rubroboletus satanas, is the classic example. Wikipedia describes a pale, velvety cap with pores that start yellow to orange and turn red to purplish red, a stem with a fine reddish net, pores that turn blue instantly when touched, and flesh that slowly turns faded blue when cut. It is described as moderately poisonous, especially raw, causing nausea, abdominal pain and violent vomiting with bloody diarrhoea lasting up to six hours. It is a European species of oak and sweet chestnut woods; Wikipedia notes that western North American collections belong to a different species, Rubroboletus eastwoodiae.

Poison Control's rule applies here too: without an expert identification of the specimen, treat a red-pored, blue-bruising bolete as a poisonous one.

The red cage stinkhorn, Clathrus ruber, looks nothing like an ordinary mushroom: a red to orange hollow ball of interlaced branches, 5 to 20 cm tall, rising from a whitish 'egg' up to 6 cm across. Wikipedia describes its smell as notoriously foul and notes it grows in mulch beds, gardens and lawns; it now occurs in North America from California to New York. Its edibility is undocumented, and Wikipedia records an 1854 account of poisoning with convulsions and temporary loss of speech. Treat it as poisonous and keep children and dogs away from it. See stinkhorn mushroom in yard.

Poison fire coral, Trichoderma cornu-damae, grows as red to orange finger-like branches rather than a cap. Wikipedia records at least two deaths in Japan, one in 1999 after 1 to 2 grams soaked in sake and one in 2000 after eating fried specimens, and names satratoxin-H as the main toxin. It was long thought to be limited to mountains in Japan and South Korea but has since been found in Indonesia, Papua New Guinea and, from October 2019, the rainforest of Far North Queensland in Australia. Wikipedia describes the claim that touching it causes a rash or chemical burns as unverified; do not handle it.

The fly agaric effects described in the sources above all follow eating it. That is not a reason to handle any wild mushroom carelessly: wear gloves or wash your hands afterwards, keep red mushrooms away from children who put fingers in their mouths, and remove them where dogs play. Do not touch poison fire coral at all.

Bright orange to orange-red mushrooms growing in tight clusters from a stump or buried wood are covered separately on eastern jack-o'-lantern and orange mushroom in yard.

A picture of the red cap alone matches half a dozen species. Take the set that MushroomIdentifier.org asks for, and add the checks that matter for red fungi:

• The cap from above, showing any white warts or patches.
• The underside, clearly showing gills or pores and their colour.
• The whole stem after digging out the base, to show any ring or bulb.
• A cut or pressed spot photographed after a minute, to show any blue colour change.
• What it grew from: soil under a tree, mulch or wood, and the nearby trees.

Then photograph it with the app. An identification tells you what to avoid; it never tells you a wild mushroom is safe to eat.