Jewelled amanitaAmanita gemmata

The jewelled amanita (Amanita gemmata), also called the gemmed or jonquil amanita, is poisonous and not edible. It contains the same compounds as the panther cap and fly agaric, ibotenic acid and muscimol, which act on the nervous system. It's a slender yellow mushroom with white flakes on the cap, a thin ring that soon disappears and a small bulb at the base of the stem. Some European books and iNaturalist list it as Amanita junquillea. Many North American mushrooms labelled 'gemmata' in field guides are now thought to be different species, so photos and reports from there don't always match the European one.

How poisonous is it? Nobody can say for sure, and that's the real danger. Field guides note that the amount of toxin varies from one find to another. Some specimens look halfway between the jewelled amanita and the panther cap, and poisonings by such intermediate mushrooms have been reported. So even a pale, harmless-looking one should be treated as poisonous. Boiling, frying and drying don't make it safe. And if you've seen it called psychedelic online, bear in mind that it's an unpredictable poisonous mushroom, not a recreational one: nobody can tell how much toxin is in a particular cap.

How do you identify a yellow mushroom with white spots? The cap ranges from pale straw to egg-yolk yellow, usually more ochre in the centre, and is slightly sticky when wet. It carries flat white flakes, but rain washes them off easily. On mature caps the margin is grooved, as if someone had run a comb along it. The gills are white, crowded and free from the stem. The stem is white or pale yellowish, with a thin, skirt-like ring that falls away with time. The most useful feature is underground: a small rounded bulb, tightly wrapped in a volva that ends in a narrow free collar at the top. That's why a suspicious yellow mushroom should be dug up whole, not cut off at ground level.

What can it be confused with? Most often the false death cap. That has a lemon-yellow or whitish cap, a ring that lasts into old age, a large bulb that looks abruptly cut off at the top, and it smells of raw potato. The panther cap has a brown cap with the same white flakes and a very similar base. Pale yellowish-brown specimens in between are hard to tell apart, but both are equally poisonous. A fly agaric bleached by rain can fade to orange or yellowish, yet it has a large hanging ring and rings of warts on the bulb. The orange and tawny grisettes have no ring at all and a tall, sack-like volva. Caesar's mushroom has yellow gills, a yellow stem and a big white sack-like volva.

For anyone picking edible mushrooms, the most dangerous mix-up is with yellow brittlegills. Once rain has washed off the flakes and the ring has gone, a jewelled amanita seen from above can pass for an ochre brittlegill or a yellow swamp brittlegill. But a brittlegill has no ring and no bulb with a volva, and its stem snaps like chalk. The yellow knight, another yellow mushroom, has yellow gills, not white ones.

Where and when does it grow? Under pines and spruces, less often in mixed and broadleaved woods with oak, beech or birch, usually on sandy, acidic soil and often along paths and forest tracks. It grows singly or in small groups. It's one of the first amanitas of the year, appearing in early summer and fruiting again, often more plentifully, in autumn; in mild southern areas it carries on into early winter. It is widespread in Europe but patchy, tied to sandy, acid soils; in Britain it turns up in coastal pinewoods on stable dunes.

What are the symptoms? They usually start between half an hour and three hours after the meal, rarely after more than six. Nausea, sometimes vomiting, dizziness, unsteadiness, agitation or confusion, seeing and hearing things that aren't there, and muscle twitching. Excitement can alternate with heavy drowsiness or even unconsciousness, and children may have seizures. Most people recover within 6 to 24 hours and deaths are extremely rare, but some patients need intensive care. If you or someone close to you, especially a child, has eaten one, call 112 (999 in the UK) straight away and don't wait for symptoms. Don't try to make the person vomit: with drowsiness or seizures that's dangerous. Lay a drowsy person on their side, don't leave them alone, and keep any leftovers or photos for the doctors. If nausea, vomiting or diarrhoea start six hours or more after the meal, something else may have got into the basket, such as a death cap: that is an emergency, even if the person later feels better.

In Chile, serious poisonings with liver damage were once blamed on this species, but they were probably caused by a different, similar amanita (Amanita toxica). We found no such cases with the European jewelled amanita in our sources, but that's no reason to take a chance.