*Psilocybe subaeruginosa*, kunanyi, southern lutruwita. Image by Caine Barlow.

A recent study conducted by Australian researchers supports claims that Australia is the birthplace of a magic mushroom…

Up for an intrepid mushroom story? Indulge us: Imagine this humble fungus embarking on a journey from the sun-drenched parks of Australia to the temperate gardens of the Northern Hemisphere, barely changing its appearance, yet being recognized as something new.

This is the story of Psilocybe subaeruginosa—the latter part of the name means "slightly verdigris-colored," a nod to the vibrant blue bruises that emerge when the mushroom is damaged. It’s a star in the world of fungi, central to countless psychedelic experiences, and part of a larger story of a fascinating global spread that can be uncovered by unweaving its genetic mysteries. But where did it originate?

The vibrant blue bruises that emerge when the mushroom is damaged.

U.S. scientists hypothesised a group of very similar psychedelic species emerged in their part of the world, while others suggest a different story - all claims made from limited genetic evidence.

And if you’re thinking, "Wait, how can anyone make claims like that based on limited data?"—you’d be on the same wavelength as the Australian mycologists who decided to settle the debate with a research study.

For a couple of decades now, some local mycologists have been pointing out exactly how similar these species are, despite some genetic evidence - ITS sequences, more on that later - claiming otherwise.

The team, led by Alistair McTaggart and featuring EGA’s very own resident mycologist Caine Barlow, decided to take the issue by the epistemic horns and explore the genetic diversity and evolutionary history of Psilocybe subaeruginosa. The goal? To determine if Australia is the likely origin from which this species spread around the world.

And like every investigation they started with a 'simple' question…

**Psilocybe subaeruginosa**

`📷 Jonathan Carmichael`

How does the genetic structure of Psilocybe subaeruginosa in Australia connect to its spread and relationship with similar species in the Northern Hemisphere (or other populations typically referred to as “Section Cyanescens”)?

To solve this, the first step is to confirm whether these global populations are genetically linked. If they are, it would demonstrate that mushroom populations from both hemispheres are part of the same species.

Once that link is clear, researchers can focus on how Psilocybe subaeruginosa has evolved in different environments over time. Some populations may develop unique traits and, in extreme cases, diverge into separate species.

However, despite geographic separation, these mushrooms still share key genetic markers, suggesting that if they crossed paths again, they could still interbreed—keeping them classified as the same species.

Hitchhiking between Hemispheres

**Psilocybe subaeruginosa**

`Chilling in some woodchips`

The plot thickens when you look at the researchers’ findings in Melbourne, Australia. There they compared two local populations—one from Geelong (about 70 km outside the city) and Clifton Hill (inner-city) —and both showed strong similarities to Psilocybe cyanescens from the U.S.

This suggests that the mushrooms didn’t just evolve independently in different regions but may have hitch-hiked across the globe through human activity.

Of course that begs the question:

'How did it travel thousands of kilometers?'.

One likely vector is Qantas... nah just joking. The answer is soil. It’s believed that the shipping of live plants, helped spread these fungi far and wide, allowing them to establish themselves in new environments across different continents.

All of this is firm proof of a genetic link between the populations. But identifying a species’ true origin is about more than just DNA; it’s a puzzle that involves historical context, fossil records, and understanding how species migrate over time. There’s more science to be done before we fully unravel this fungal mystery—but the evidence is building.

It's time to call in the forensics team.

Let me tell you a Genetic Secret.

Armed with the hypothesis that these mushrooms from different hemispheres are the same species, researchers focussed on eastern Australian populations of Psilocybe subaeruginosa. Why? Compared to populations from other regions, the eastern populations are more genetically similar to each other.

That tantalising fact suggests they share a common evolutionary history that may provide insights into how the species adapted and spread globally. (Think of it like discovering a hidden family tree: if you find that several branches of a family are closely related, it reveals a shared history).

So they dived in…

**The researchers were ready to uncover the secrets of Psilocybe subaeruginosa by utilising three bioinformatic methods:**

Genetic Differentiation (FST)
This measures how distinct different populations are from one another, shedding light on their history and relationships.

Nucleotide Diversity (π)
This gauges the level of genetic variation within a population, offering insights into how well a group might adapt to environmental changes.

Tajima’s D:
This evaluates whether the genetic diversity in a population aligns with expected patterns, revealing signs of evolutionary processes, such as balancing selection (meaning maintaining diversity in traits that can help a species survive in changing environments).

And then…

Dusting for fingerprints

To understand how Psilocybe subaeruginosa relates to other populations, researchers zoomed in on a specific part of the mushroom’s DNA: the Internal Transcribed Spacer (ITS) region, which acts like a fingerprint for fungi.

The ITS region became the fungal molecular barcode because it is usually stable within a species and different between other species. But here’s where things got interesting: the study found surprising variation in the ITS region of Psilocybe subaeruginosa and related species. This suggests that the ITS region is not a good marker for differentiating new species; the same individual mushroom can have two different copies, making it harder to draw a line between species.

This implies that even though these mushrooms are found in different hemispheres, they still share a common origin. That already challenges the old assumption that the U.S. varieties are separate—and opens the door to Australia potentially being the true homeland of these magical fungi.

SIDE NOTE

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SIDE NOTE 〰️

A byproduct of this finding is that researchers have shown the ITS region is a good marker for identifying Psilocybe to a species-level taxonomic rank but not as the foundation for taxonomic changes. Imagine a facial recognition system that’s normally great at identifying different people. However, when it’s used on identical twins, it struggles because the differences are so subtle. Similarly, the ITS region typically helps researchers identify different species within a genus, but with closely related species like those in the Psilocybe genus, the differences are enough that the region becomes unreliable for telling them apart. As a result, some newly named species based on small changes in ITS might just be slight variations of the same one.

This study suggests that conducting a population genetic analysis of past gene flow is the most reliable method for understanding species boundaries.

So… what can we glean from all of this? The genetic differences within the ITS region are found in many types of fungi. Mushrooms from eastern Australia appear more similar to each other than their regional counterparts, yet they boast a surprising richness in genetic diversity compared to those in the Northern Hemisphere.

That already sounds like magic but the truth is more scientific.

The Clues of Father Time

***Actual photo of Father Time leaving clues in*** ***Psilocybe subaeruginosa's*** ***genetic footprint...***

Australian mushrooms have had the luxury of a more extended evolutionary journey; its genes shaped by lengths of time its Northern Hemisphere relatives are yet to experience. This deep genetic diversity is akin to battle scars, each variation embedding a survival story crafted over millennia, leaving behind little evolutionary breadcrumbs for researchers to follow.

And these breadcrumbs followed all the way Down Under. In short: compared to other global populations, it supports that the Australian populations have been around for much longer.

A significant takeaway from this research is that species from the Northern Hemisphere—Psilocybe cyanescens Wakefield, known as “Wavy Caps,” and Psilocybe azurescens Stamets & Gartz, known as “Flying Saucers”—are conspecific with Psilocybe subaeruginosa. Essentially, they can be considered the same species.

So, sorry Northern Hemisphere: this study proves that Australia is the cradle from which Psilocybe subaeruginosa first evolved, diversified, and spread from.

Next time you go foraging in Australia, know that you are picking straight from the magic source.

To read the full study “Fungal Systematics and Evolution” - Click Here.