Update: Another likely death cap mushroom has been found in the same Boise neighborhood as last year. Susan Stacy, the same woman who first discovered the fungus in the Mountain West, has found it along the busy residential street Harrison Blvd. It has not been DNA-confirmed yet.
Toxic mushrooms are not unusual in the Mountain West.
鈥淭his is probably a ," said Susan Stacy, looking at a mushroom on a recent afternoon in a Boise, Idaho, neighborhood not far from downtown. "See that little dark nub in the middle and little flecks around here?鈥�
Stacy turned to her mushroom identification book.
鈥淓dibility: to be avoided. Perhaps poisonous,鈥� she said.
While this little mushroom could be problematic for a curious dog or child, it doesn't compare to one of the world鈥檚 deadliest mushrooms 鈥� which Stacy discovered in Boise last September.
She remembers that it was a hot day, and she decided to take a detour from her normal route to check out a busier area where many lawns were 鈥済enerously鈥� watered.
鈥淎nd here I come upon this mushroom, and I knew it was an Amanita because I had seen them before. And an Amanita, to my mind, is a gorgeous, statuesque, elegant creation. They're just stately,鈥� she said.
The genus Amanita includes, incidentally, the species on which the red and white mushroom emoji is likely based, which also happens to be .
So Stacy dug the mushroom up, careful to collect a little tissue sack that was around the base.
鈥淚 got out my Mushrooms Demystified book by David Arora,鈥� she said, 鈥渁nd my mushroom fit his description of Amanita phalloides. So I said to myself, 鈥極h, cool! I found this species of Amanita.鈥欌€�
What she didn鈥檛 initially realize was how serious that was. Amanita phalloides, known as the death cap, is often as killing more people than any other mushroom on earth. And before last fall, it hadn鈥檛 been identified in the Mountain West.
Just to be sure it was a death cap, a former pathologist named Mickey Myhre later helped confirm it using DNA analysis, which is a growing sector in mycology.
鈥淲hen I started trying to learn about identifying mushrooms, I thought, 鈥楾his is impossible, all these keys and codes. There's got to be a better way,鈥欌€� he said. 鈥淎nd then I started reading about DNA barcoding and I thought, 鈥楢h, there's a shortcut!鈥欌€�
Myhre said mushroom DNA is an area where there鈥檚 still plenty to learn, but when it came to testing the suspected death cap, 鈥淲e got between 99.85% and 100% match on the DNA sequence. And so by anybody's criteria, it would be a good solid match.鈥�
DNA confirmation is important because a lot of mushrooms are easily misidentified or even completely unnoticed.
Many mushroom species are still unknown, and one entire category is listed as 鈥渓ittle brown mushrooms,鈥� or LBMs.
It鈥檚 also still unknown what invasive mushroom species, like the death cap, might mean for trees and ecosystems.
That鈥檚 according to Anne Pringle, a University of Wisconsin professor who studies the spread of the death cap. She confirmed that it isn鈥檛 native to the U.S.
鈥淚 collected a lot of population genetics data and established that it was an introduction from Europe," she said. "It's particularly interesting because in California it's shifted hosts.鈥�
That is, since the death cap was first identified there in the 1930s or 1940s, it has started making friends with the native tree species. Pringle said that could be something to watch for in places like Boise, too.
The death cap has a symbiotic relationship with certain tree roots 鈥� like hornbeams and oaks 鈥� which means they give and take nutrients.
鈥淚t鈥檚 a mycorrhizal fungus, so it's one of those fungi that people hear about that associate with trees and provide benefits to trees in exchange for carbon compounds,鈥� Pringle said.
But the death cap鈥檚 underground root-like mycelium only produces mushrooms when its host tree matures. So it鈥檚 probably been underground in Boise for decades already, ever since trees were imported from California.
Use your thinking cap
Krista Willmorth is president of the Southern Idaho Mycological Association. She says one association member had even warned that it might show up.
鈥淏ob Chehey had always been telling us 鈥榳e don't have it, but we don't have it yet,鈥欌€� she said. 鈥淲e have the conditions for it. Certainly seems like it could appear. And indeed it did.鈥�
She said that cities like , have found that once it鈥檚 there, it's impossible to eradicate, even with fungicide.
鈥淔ungicides are not going to help. They're just going to add more poison to your environment,鈥� she said.
Because of that, it鈥檚 important for people to identify death caps, and not eat them 鈥� . It doesn't help that they delicious.
The mushroom is generally a few inches tall. The cap鈥檚 color is a light yellowish with a green tint and a sort of metallic sheen. But, it can get a little darker and duller with age.
Underneath is white gills and often a little white skirt around the stocky stem. And then there鈥檚 a little white tissue sack holding the base of the stem.
鈥淎s it grows up and pops up, it breaks that sack. And on these, that little sack remains around the bottom,鈥� Willmorth said.
For those who still aren鈥檛 sure, they can also check the spore color. Just pop off the cap, place it gills-down on a piece of paper or foil, and cover with a bowl for a few hours. Spore prints are like fingerprints for mushrooms, and the spore color of death caps is white.
Of course, if you suspect someone has eaten a death cap, immediately call .
In 2016, grew sick in a two-week period after eating death caps. Three needed liver transplants, and one young girl suffered permanent neurological damage.
Luckily, you can touch, pluck and throw away any mushroom without consequence, as long as you don鈥檛 eat it. Picking a mushroom doesn鈥檛 hurt the underground organism.
You can also reach out to a local mycological association or post to iNaturalist for help identifying the fungus so local residents can be warned.
But all of this requires residents to keep an eye out. That includes Susan Stacy in Boise, who is now working with the city parks department and others to monitor old oaks around neighborhoods.
鈥淲hen you say that you're an amateur mycologist, there's a certain pride in that,鈥� she said. 鈥淚 think we have a great opportunity here to contribute something new to science.鈥�
There鈥檚 agreement among mushroom aficionados that there aren鈥檛 enough certified experts to go around, and community scientists like Stacy have to step in to help identify mushrooms around the world.
Stacy had been looking at mushrooms in Boise since the '80s, when she found the particularly odd 鈥� and somewhat adorable 鈥� . She may call herself an amateur with pride, but she has been interested in fungi longer than many mycology Ph.D.s in the field.
While there isn鈥檛 one official international mapping system for fungi, many post them on or .
So far, the only verified death caps in the Mountain West have been found in Boise in a few separate patches, but at least one other was flagged on iNaturalist just east of Salt Lake City.
and in New Mexico have reported a rash of other toxic mushroom blooms and poisonings, thanks to the monsoon season.
So as always, do not eat any mushrooms you can鈥檛 100% identify. If there is any doubt, and you still want to eat it, ask someone who knows better.
鈥淵ou will not appear dumb or or stupid, or anything like that, if you ask somebody who knows,鈥� Stacy said. 鈥淏ecause your life is worth not getting sick over.鈥�
This story was produced by the Mountain West 暗黑爆料 Bureau, a collaboration between Wyoming Public Media, Boise State Public Radio in Idaho, KUNR in Nevada, the O'Connor Center for the Rocky Mountain West in Montana, KUNC in Colorado, KUNM in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West 暗黑爆料 Bureau is provided in part by the .
Copyright 2022 Boise State Public Radio 暗黑爆料. To see more, visit . 9(MDAxNDQ2NDAxMDEyNzU2NzM2ODA3ZGI1ZA001))