Look-alikes
The pairs, and what actually separates them.
16 pairs, 7 of them lethal, ordered by consequence. Each page gives the separating features in the order you should check them, starting with the one that settles it fastest.
Gyromitrin, which the body converts to monomethylhydrazine
True morel
Morchella species
mistaken for
False morel
Gyromitra esculenta and relatives
Vomiting and vertigo after several hours, and in serious cases liver damage, haemolysis and death. The toxin is volatile and cumulative, so people who ate it for years without trouble are still poisoned by it. Cooking reduces but does not reliably remove it, and the vapour alone has hospitalised cooks.
3 separating features, most decisive first
Amatoxins, the same class as in the death cap
Honey mushroom
Armillaria species
mistaken for
Deadly galerina
Galerina marginata
A deceptive delay. Symptoms often hold off six to twenty-four hours, by which time the toxin has been absorbed and the liver is already being destroyed. There may then be a false recovery before organ failure. Treatment is intensive and transplant is sometimes the only option.
3 separating features, most decisive first
Amatoxins
Puffball
Calvatia, Lycoperdon species
mistaken for
Amanita button
Amanita phalloides, A. bisporigera and relatives
The death cap and the destroying angels account for the overwhelming majority of fatal mushroom poisonings worldwide. A single cap can kill an adult. Symptoms are delayed, then appear to improve, then the liver fails.
3 separating features, most decisive first
Amatoxins
Meadow mushroom
Agaricus campestris
mistaken for
Destroying angel
Amanita bisporigera and relatives
Delayed onset, apparent recovery, then liver and kidney failure. One of the deadliest mushrooms on earth, and it grows in grass alongside the edible one.
3 separating features, most decisive first
Amatoxins, the same compounds as in the death cap
Parasol
Macrolepiota procera
mistaken for
Deadly dapperling
Lepiota brunneoincarnata and relatives
Delayed vomiting after six hours or more, an apparent recovery, then liver failure. The mushroom is the size of a thumbnail, which is exactly why nobody takes it seriously enough.
4 separating features, most decisive first
Orellanine
Chanterelle
Cantharellus species
mistaken for
Deadly webcap
Cortinarius rubellus, C. orellanus
Nothing for two days to three weeks, then kidney failure. The delay is the longest in mycology, and it means the meal is almost never connected to the illness. Serious cases end in dialysis or transplant.
4 separating features, most decisive first
Allenic norleucine and related compounds
Matsutake
Tricholoma murrillianum
mistaken for
Smith's amanita
Amanita smithiana
Vomiting after several hours, then kidney failure developing over the following days. Cases regularly require dialysis, and some do not recover full kidney function.
4 separating features, most decisive first
Illudin S
Chanterelle
Cantharellus species
mistaken for
Jack-o'-lantern
Omphalotus illudens / olearius
Violent vomiting, diarrhoea and cramps beginning within a few hours. Rarely fatal, but people are hospitalised for dehydration every year, and it is one of the most common poisonings in both North America and Europe.
4 separating features, most decisive first
Unidentified gastrointestinal toxins
Shaggy parasol and parasol
Chlorophyllum rhacodes, Macrolepiota procera
mistaken for
Green-spored parasol
Chlorophyllum molybdites
Severe vomiting and bloody diarrhoea for hours. Rarely fatal but frequently hospitalising, and it is the most commonly eaten poisonous mushroom in North America, largely because it fruits in suburban lawns where people find it.
3 separating features, most decisive first
Unidentified gastrointestinal toxins, with liver damage reported at high doses
Honey mushroom
Armillaria species
mistaken for
Sulphur tuft
Hypholoma fasciculare
Severe vomiting and cramps for hours. Rarely fatal, and its saving grace is that it is ferociously bitter, so most people spit out the first mouthful.
4 separating features, most decisive first
Muscarine, at a far higher concentration than the fly agaric contains
Fairy ring champignon
Marasmius oreades
mistaken for
Ivory funnel
Clitocybe dealbata, C. rivulosa
Sweating, streaming eyes, heavy salivation, pin-point pupils and a slowed heart within half an hour. Distressing, occasionally dangerous in the frail, and it responds well to atropine in hospital.
4 separating features, most decisive first
An unidentified compound affecting the brain, likely an amino acid
Oyster mushroom
Pleurotus ostreatus
mistaken for
Angel wings
Pleurocybella porrigens
Regarded as edible for decades until an outbreak in Japan in 2004 caused encephalopathy and seizures, with seventeen deaths. Nearly all those affected had existing kidney disease. It has been treated as a mushroom to avoid ever since.
4 separating features, most decisive first
Unidentified gastrointestinal toxins
Puffball
Lycoperdon, Calvatia species
mistaken for
Common earthball
Scleroderma citrinum
Strong vomiting, cramps and diarrhoea within a few hours. Rarely dangerous, frequently dramatic, and occasionally sold to restaurants as truffle by people who should know better.
3 separating features, most decisive first
Unidentified gastrointestinal toxins
St George's mushroom
Calocybe gambosa
mistaken for
Livid pinkgill
Entoloma sinuatum
Violent and prolonged vomiting and diarrhoea, sometimes lasting days and requiring hospital treatment. Responsible for a large share of serious poisonings in Europe.
4 separating features, most decisive first
Ibotenic acid and muscimol
Caesar's mushroom
Amanita caesarea and relatives
mistaken for
Fly agaric
Amanita muscaria
Confusion, agitation, distorted perception, deep sedation and vomiting for up to a day, occasionally seizures. Deaths are very rare, but this is a poisoning that puts people in hospital overnight.
3 separating features, most decisive first
Coprine, which blocks alcohol metabolism in the way the drug disulfiram does
Shaggy mane
Coprinus comatus
mistaken for
Common inkcap
Coprinopsis atramentaria
Harmless eaten by itself. Combined with alcohol at any point in roughly the following three days it causes sudden flushing, a pounding heart, headache, nausea and a strong sense of impending doom.
3 separating features, most decisive first