Rare purple mushroom found in Arizona for 1st time: 'Beautiful as a delicate wildflower'

A rare dark purple mushroom has been documented in Arizona for the first time.

As reported by This Is Tucson, a senior at the University of Arizona was foraging with friends in the Santa Catalina Mountains last summer when she discovered the small, vibrant, purple-capped stems tucked in the shade under a log.

Turns out, no one has seen this mushroom in Arizona until now — or if they did, it has not been submitted to a DNA sequence database. What the student, Caitlin Dowd, had found appears to be an Entoloma occidentale variety metallicum.

Or, as Betsy Arnold describes it, “It’s a super beautiful purple mushroom. It’s as beautiful as, like, a delicate wildflower.”

Arnold is the curator of the Robert L. Gilbertson Mycological Herbarium at the University of Arizona in Tucson and a professor in the School of Plant Sciences.

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What is Entoloma occidentale, or purple mushroom?

It can be difficult to identify fungi only by sight, so Dowd and her friends reached out to some online forums to share their observations and solicit help.

Identifying the mushroom took some back-and-forth between iNaturalist users and local mushroom experts who debated the mushroom's species based on submitted images. They ultimately concurred, based on photos and DNA sequencing, that it must be the Entoloma occidentale variety metallicum.

According to a species fact sheet published by the USDA Forest Service, “Entoloma occidentale is rare. It belongs to a group of colorful fungi that are often picked up but are seldom properly identified.”

Dowd’s specimen is the first that has been recorded in Arizona, and her finding helps scientists understand the species.

“Who knows; this may end up being multiple species in the future, once people do more work," Arnold said.

"But for now, the species has these different varieties, and the different varieties occur in different parts of the U.S., but they're really not considered very common. We don't have a lot of scientific information about this, and Caitlin’s finding really adds a lot to it.”

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Where are these purple mushrooms found?

Typically, the Entoloma occidentale can be “found in low to mid-elevation mixed conifer-hardwood stands,” according to the Forest Service.

These mushrooms aren't widely distributed and “can't jump from mountain to mountain by themselves,” according to Arnold. Instead, they have spores that distribute locally. That means Dowd was at the right place at the right time when she found the Entoloma occidentale.

“If I had to guess — and this is speculation — I would say that probably these have been here over the history of the forests in Arizona, and they may be scattered throughout our beautiful high elevation sites,” Arnold said.

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Is the purple mushroom poisonous?

A good rule of thumb is to never eat a mushroom or plant you can't definitively identify.

"Entoloma mushrooms are best avoided, as there are many poisonous species in the genus," Arnold said.

What the purple mushroom’s discovery means

When Dowd found the purple mushroom, she didn’t only take photos of the discovery; she worked with others in the community, including Arizona Mushroom Society Chair Terri Clements, to document every detail about the mushroom's DNA and where it was found.

“Terri is the most knowledgeable mushroom enthusiast I've ever met,” Arnold said. “My understanding is that she helped Caitlin realize that this was something new.”

In what Arnold called “a beautiful team effort,” Clements stepped in to ensure the mushroom’s DNA was captured. This “gives it a DNA sequence that's actually in the DNA sequence database, the most important one in the country,” Arnold said.

Clements also deposited a permanent specimen of the fungus to the University of Arizona’s Mycological Herbarium. The herbarium is home to what Arnold calls “a vibrant, dynamic collection” of more than 40,000 dried fungal specimens.

“That means that we have a scientific record that can be studied for generations to come,” Arnold said. "With this specimen now, someone could come back in 25 years and recognize that maybe the name needs to change because other diversity has been discovered. And it kind of contextualizes where this one goes.”

Dowd’s finding helps scientists understand how fungi in certain areas change over time.

“Our forests here in Arizona are under such pressure from fire and climate change. And as the forests undergo these massive changes, it's possible that some of the species we have in the herbarium — the mycological herbarium — we'll never see again out in nature,” Arnold said.

“Caitlin's discovery is a wonderful reminder that keeping our eyes open and being curious can help us discover treasures of biodiversity in our beautiful state,” she said.

What to do if you find a unique-looking mushroom

Anyone who stumbles upon an unusual plant, mushroom or creature out in the wild should take a photo and submit it to iNaturalist, a network of citizen scientists and biologists who share photos and observations of biodiversity they find around the world.

Many mushrooms in mountains become visible during rainy seasons, like during Arizona's monsoon.

“It would be great to have people keeping an eye out and grabbing a photo (of the Entoloma occidentale) as they're in the highest elevations of our beautiful mountains,” Arnold said.

If you happen to see a mushroom that looks like the Entoloma occidentale, there’s no need to disturb it; submitting a photo will help scientists learn more about the species.

“We know it's in Arizona, but we don't know if it's anywhere else beyond Mount Lemmon,” Arnold said.

“A wonderful thing to do would be to take a photo and upload that to iNaturalist. That way, we start to have a body of observations beyond what we have so far. And we'll know, for example, that it lives in places we never realized, and that helps us understand more about it.”

Reach Entertainment Reporter KiMi Robinson at kimi.robinson@gannett.com. Follow her on Twitter @kimirobin and Instagram @ReporterKiMi.

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This article originally appeared on Arizona Republic: Rare purple mushroom discovered in Arizona for the first time