The Deathcap situation - a super long post
If you've read the news lately, you're probably aware that there's a flush of Deathcap mushrooms in California right now, which has poisoned at least two dozen people.
(photo by inaturalist user federicocalledda)
I'm somewhat frustrated by the articles I've read about it, though, since they don't do a good job of describing why people get poisoned by these. Even the article that I linked says, "... they don't look too different from other kinds of harmless mushrooms." The New York Times article about this was even worse. They do, in fact, have a very distinctive appearance, and I want to talk about that later. But first, the gory details:
Deathcaps, Amanita phalloides, have Ī±-Amanitin (alpha-Amanitin), which is not specific just to them - it's also found in the Destroying Angels, like Amanita virosa (the European Destroying Angel) and Amanita ocreata (the Western Destroying Angel) and some mushrooms that aren't even Amanitas, like Galerina marginata.
What makes this amatoxin, especially Ī±-Amanitin, so dangerous is that it's "sneaky" - when people eat Deathcaps, they usually get nasty gastrointestinal issues for a day or two, and then they feel better. Meanwhile, the Ī±-Amanitin is binding to RNA polymerase II, which prevents m-RNA synthesis. This is important because it essentially slowly destroys a person's hepatocytes, so it slowly causes liver failure, and prevents the liver from repairing itself. By the time they get sick again, it's too late, and they probably need a liver replacement. It also causes kidney failure. Not a fun way to go!
I'm sure we all remember how the Australian Erin Patterson used iNaturalist to find Deathcaps to kill her family members a couple years ago. But there have been a number of historical figures supposedly killed by it as well, like the Roman Emperor Claudius and Charles VI, Holy Roman Emperor. When historians read about their deaths, they generally look for the "two-stage" poisoning for the indication that what killed these people was Deathcaps, and not a different poison.
Deathcaps taste really good when you eat them, which may be the reason for the War of the Austrian Succession.
Why are people mistaking these for safe mushrooms, though? A lot of the articles about Deathcap poisoning don't really go into this, they just warn you not to eat any foraged mushrooms, which I don't think is super useful. One of the major problems with Deathcaps is that they're only native to Europe, but their population in places they've been introduced is expanding, and people may not realize they need to be careful to avoid them in places like North America.
It appears that there are several species that people commonly confuse the Deathcap for. Deathcaps, being Amanitas, have a universal veil that covers the entire mushroom in the early "egg stage" and may leave some veil fragments on older basidiocarps, as well as forming an annulus/ring on the stipe/stem. They have a large, sack-like volva around the base - also a remnant of the veil. The cap can be whitish, greenish, yellowish, or brownish in color.
(Deathcap photo by inaturalist user shane_marshall)
Most poisonings aren't caused by confusion with a local mushroom - they're caused by recent immigrants from Asia confusing this with paddy straw mushrooms, Volvariella volvacea, which are cultivated in Southeast Asia and look similar. PADDY STRAW MUSHROOMS ARE NOT NATIVE AND DO NOT COMMONLY GROW IN WESTERN NORTH AMERICA OR AUSTRALIA. So if someone tells you they picked a paddy straw mushroom there, that's a HUGE red flag.
(Volvariella volvacea photo from Mycelia (https://mycelia.be/m5100-volvariella-volvacea/))
There are also several "edible" Amanitas that even foraging "experts" may think they're picking when they're actually picking Deathcaps. Just in general, I think it's wise to avoid eating Amanitas because a lot of the tricks you'd use to avoid Deathcap aren't usable when picking these. Flimsy texture? Yep. Volva? Yep. Fragment of universal veil? Yep. Yeah, these are a solid No from me. But here are some of them, for reference:
(clockwise from left, Amanita pachycolea and Amanita calyptroderma by Michael Wood on Mycoweb, Amanita velosa by Christian Schwarz on iNaturalist, and Amanita fulva by Benjamin Eiche on iNaturalist)
I personally, as someone who won't eat Amanitas at all, wouldn't mess with the edible Caesar mushrooms, but here they are if you're curious (you can see these don't really look like Deathcaps given their orange color!):
(Amanita caesarea by Davide Puddu on iNaturalist and Amanita jacksonii by Zac Cota on iNaturalist)
Sometimes, people mistake the egg stage of deadly Amanitas for puffballs, like Lycoperdon perlatum or even Calvatia species.
(Lycoperdon perlatum and Calvatia booniana by Fred Stevens on Mykoweb)
I'm not sure which Amanita this is, but I found a Reddit post by user neckbeardninja that shows this well https://www.reddit.com/r/mycology/comments/16wl70a/forbidden_puffball_amanita_egg/:
Not a puffball! Yikes!
Lastly, while not often confused with Deathcaps, foragers may think they've found a Matsutake or Big Cat when actually they've found one of the many poisoning white Amanita species.
(I love this photo in iNaturalist by Mike Potts of Western Matsutake on the left, Tricholoma murrillianum. Tricholoma magnivelare looks very similar. Catathelasma ventricosum on the right by Michael Wood on Mykoweb)
You shouldn't pick Matsutake if you're not extremely confident about your identification skills. It should smell kinda funky, like socks or cinnamon, have a sandy and tapered base and not a wide volva like an Amanita, be dense and hard and not fragile and easy to crush. I personally wouldn't pick Matsutake, despite feeling confident in my id skills, because it looks so similar to these poisonous Amanitas:
(Amanita smithiana by Christian Schwarz on iNaturalist, Amanita ocreata by Michael Wood on Mykoweb)
Sure, those have universal veil fragments and bulbous bases instead of tapered ones, but would you really want to bet your liver on it? While researching the current flush, I found an article from a few years ago that mentions a woman who was poisoned by an Amanita after collecting what she thought were chanterelles, matsutakes and hedgehog mushrooms. She thinks she mistook an Amanita for a hedgehog mushroom, which makes no sense because hedgehogs have "teeth" and not gills. I'd be willing to bet my whole next-years Lobster haul that the mushroom she messed up on was the "matsutake."
Anyway, stay safe out there and avoid a succession crisis by not playing the "I think it's X but I'm not sure, let me ask Facebook" game.
