This magic mushroom can kill

That species had not been reported in Florida before, Kunik says. “It’s quite rare and unusual.” He also found two other new related species, tagged with the placeholder names Galerina species 1 and Galerina species 2.

Other researchers had previously described G. indica’s appearance and found DNA signatures that distinguish the fungus from related species. But no one had cataloged the mushroom’s complete chemical or genetic makeup.

Related Galerina species make amatoxins, deadly chemicals that can kill in even tiny amounts and are found in death cap mushrooms and other species. Kunik and colleagues looked for those toxins in G. indica and the two other new Galerina species. G. indica makes a previously undiscovered form of amatoxin the team is calling alpha-proamanitin, the chemical analysis revealed.

The small mushroom also had blue bruises, a clue that it might make psilocybin, a psychedelic chemical being tested as a treatment for mental health disorders. Fungi usually make either amatoxin or psilocybin. Not both. Galerina species 1 also makes psilocybin but doesn’t make amatoxin, and species 2 makes neither.

“This finding shows that there’s a lot more diversity in [fungal] chemistry and the ways that they’re combined than we had really thought about,” says Anne Pringle, a mycologist at the University of Wisconsin–Madison who was not involved in the work.

Discovering these dual compounds in one mushroom was both exciting and required further analysis to confirm, Kunik says. “Surprising discoveries require great depth of evidence,” he says.

A complete workup of the mushroom’s DNA revealed genes for producing both types of chemicals. Ancestors of these dark magic mushrooms probably picked up those genes by swapping DNA with other species. Such DNA swapping, called horizontal gene transfer, is one way that organisms can quickly evolve new traits, like when bacteria exchange antibiotic resistance genes with unrelated species.

Ancestors of G. indica and its relatives probably acquired amatoxin genes early on. Those toxins are made by many of G. indica’s cousins, which indicates that amatoxins are probably heirlooms passed down from common ancestors. Ancestors of species 1 and species 2 seem to have dropped the amatoxin genes at some point since they no longer make the compounds.

The two psilocybin-producing species may have independently obtained the psychedelic genes in separate DNA swap meets, or a common ancestor may have picked up the genes and then passed them down to G. indica and species 1. There’s not enough known about the fungi’s family tree to sort out which scenario is correct.

And there’s another unsolved evolutionary mystery, Pringle says. “We still don’t know why mushrooms are poisonous.” Many scientists think it is for defending against predators, but hard evidence is lacking, she says.

“Can I eat it?” is often the first question people ask when finding a new mushroom, Pringle says. “I’m always so uncomfortable with that question and that conversation. And this paper confirms that, in fact, you should be uncomfortable.” After all, eating these dark magic mushrooms could send people tripping into the grave.

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