Rare Purple Mushroom Documented in Arizona for First Time

Rare Purple Mushroom Documented in Arizona for First Time

Brandon Rich
Brandon Rich
January 06, 2023
2 min

Mushroom foraging can be a mixed bag. Sometimes, wild mushroom foragers find what they’re looking for, and sometimes, they don’t. Then, there are those infrequent occasions when they stumble upon something unintended — like the case of a rare purple mushroom recently found in Arizona.

As reported initially by This is Tucscon, Caitlin Dowd, a student at the University of Arizona, discovered the beautiful purple mushroom last year while foraging in the Santa Catalina mountains. At the time, Dowd was with her local club, the MycoCats.

The amazing purple wonder that appeared before her is of the mushroom species Entoloma occidentale variety metallicum. Dowd’s finding is the first documentations of this mushroom in Arizona and one of the four times ever recorded in the country. To see her original photos, check out the photo gallery on Arizona Central.

What is Entoloma occidentale variety metallicum?

The mycologists verified the identity of this rare purple mushroom at the Arizona Mushroom Society, which registered a sample in the DNA sequence database. In appearance, the variety is a metallic violet with gills.

A facts sheet published by the USDA Forest Service reports that Entoloma occidentale tends to grow in low-to-mid elevation conifer hardwood stands. Dowd’s Mount Lemmon discovery, however, would be considered high elevation.

The Forest Service data notes that these little mushrooms, with 20 to 30 mm caps when grown, are odor- and tasteless. It is certainly not an edible mushroom, as many species in the genus are toxic.

Upon examination of a Entoloma occidentale spore print, scientists have found that the mushroom has angular, ellipsoid shaped spores. As it goes, these particular spores may be one of the reasons why these mushrooms are so uncommon in Arizona.

Why is it rare in Arizona?

rare purple mushroom arizona 1
Leptonia carnea, a visually similar variety to Entoloma occidentale from Mushrooms, Demystified

Betsy Arnold is a professor in the School of Plant Sciences at the University of Arizona in Tucson and the curator of the Robert L. Gilbertson Mycological Herbarium (where a permanent specimen of the mushroom is deposited).

In comments to AZCentral.com, Arnold explains why Entoloma occidentale may be considered rare. Arnold, who calls the purple mushroom a “delicate wildflower,” points towards distribution as a reason why it doesn’t typically grow in Arizona.

According to her, these mushrooms have spores that disperse locally, meaning they won’t travel from place to place without help. But this isn’t the only reason the variety is so uncommon in the Copper State.

Arizona isn’t known as a very wet area — an environmental condition which many mushrooms, especially Entoloma occidentale, need to thrive. Yet, Terry Clements, the vice president of the Arizona Mushroom Society reported that the state’s recent monsoon season was irregularly wet. The unusually high moisture level resulted in better fruiting conditions for exciting fungi like this.

And as the USDA Forest Service data suggests, this rarity may even come down to a lack of identification. Entoloma occidentale are members of a “colorful fungi that are often picked up but are seldom properly identified.”

What the identification of Entoloma occidentale means

So, what does Caitlin Dowd’s discovery of this rare purple mushroom indicate?

For mycology, the Entoloma occidentale variety metallicum discovery in Arizona shows just how rich the region’s biodiversity is — and how a changing environment affects the biome. As new mushroom species become discovered here, this variety will serve as a link in their identification.

As for Dowd, who plans to work for the National Park Service one day, the discovery motivates her to continue her hobby as a citizen scientist. This psychedelic-looking shroom may not have any documented levels of psilocybin, but it’s still a magic mushroom in its own right.

Fact Checked: Seraiah Alexander


Brandon Rich

Brandon Rich

Content Writer

Table Of Contents

What is Entoloma occidentale variety metallicum?
Why is it rare in Arizona?
What the identification of Entoloma occidentale means

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