Psilocybe mexicana mushroom
Photo by Alan Rockefeller

Psilocybe Mexicana: History, Potency, Cultivation and More

Curandera Maria Sabina first introduced mycologists R. Gordon & Valentina Wasson to Psilocybe Mexicana in the 1950s, he shared his story with the world, and the rest is history.

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Updated May 22, 2024

Psilocybe Mexicana (aka Mexican Mushrooms) History and Biology

As with many of the Psilocybe species known today, Psilocybe mexicana grows natively in areas of North and Central America, where it has been used in indigenous cultural practices for over 2,000 years. Psilocybe mexicana was collected by Valentina Pavlovna Wasson and her husband Roger Gordon Wasson during a two year journey around Mexico (1953-1955) that included their visit to Maria Sabina, the Mazatec curandera credited with introducing psilocybin mushrooms to the world. After their trip (in both senses of the word), the Wassons sent samples of P. mexicana to the French mycologist Roger Heim, who returned to Mexico to characterize the species and cultivate it under laboratory conditions in the following years. Lab-grown samples were then sent to the Swiss chemist Albert Hofmann who self-experimented with the mushrooms, before extracting and characterising psilocybin and psilocin in 1958, 20 years after he first synthesised LSD.

Read: Psilocybin Isn’t the Only Compound in Magic Mushrooms—Here’s What Else There Is

Psilocybe mexicana is a species in the group of psilocybin mushrooms (also including P. tampanensis, and to a lesser extent P. cinctulus) that are known to produce sclerotia—hardened masses of mycelium that function in nature as a way for the organism to survive unfavorable conditions (nutrient depletion, drought, freezing, etc). You may hear the sclerotia of these species also called truffles, but technically this is a biological misnomer. From a mycological perspective, unlike sclerotia, truffles are reproductive structures—subterranean spore containers that spread their genetic payload through consumption by animals and subsequent excretion into new environments. True truffle-producing species are typically ectomycorrhizal,meaning their existence relies on a symbiotic relationship with specific host tree species. Though identified in close proximity to a variety of trees, P. mexicana’s preferred habitat is manure-rich grassland, which caused Paul Stamets to nickname these the “Mexican liberty cap” due to the two species’ affinity for similar environments.

Psilocybe Mexicana Legality

psilocybe mexicana mushroom
Photo by Alan Rockefeller

In most countries where psilocybin containing mushrooms are currently illegal, P. mexicana is no different. One exception to this is in the Netherlands, where the sclerotia themselves are legal, despite psilocybin-containing mushrooms (including P. mexicana and 185 other species) being illegal since 2008. When the ban was enacted by the Dutch government, sclerotia were excluded on the basis that they were considered to be weaker than mushrooms; but as you’ll read in the potency section, this may not always be the case!

Read: Psilocybe Cubensis & More: 10 Magic Mushroom Species You Should Know About

The legal exemption of sclerotia in the Netherlands has supported a large industry, with many “smart shops” around Amsterdam and beyond selling packets under names like Mushrocks, High Hawaiians, and Dragon’s Dynamite with various claims to differences in subjective effects. In addition to smart shops, a number of “truffle retreats” have opened in recent years, where participants can consume the sclerotia while taking part in a range of programs, under the guidance of trained facilitators and therapists. Examples include Synthesis (who opened their doors in 2018), in addition to Field Trip Health who are set to open their own retreat in 2021.   

Psilocybe Mexicana Identification

psilocybe mexicana mushrooms
Photo by Alan Rockefeller

The sclerotia produced by P. mexicana are a lumpy bundle of densely packed mycelium, which can range in size from smaller than a pea to as large as an ostrich egg, but are rarely as uniform in shape. The color of sclerotia seems to depend on growing conditions, and can range from light yellow to dark brown, and even blue in places. Due to their irregular shape, size, and color, a positive identification is rarely possible from the sclerotia alone (for that we must look at the mushrooms themselves).

As the “Mexican liberty cap”, P. mexicana shares some similar features with its more globally distributed namesake. P. mexicana are tall, thin mushrooms with straw-colored stems capable of growing up to a maximum height of around five inches. Their caps are convex or cone-shaped, sometimes with a raised area in the middle (umbonate) or margins that flare out to resemble a bell (campanulate). Like all psilocybin producing species, P. mexicana mushrooms have a purplish black spore print and bruise blue when damaged.

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For all those wanting to try and find mushrooms in the wild, psychoactive or edible, it’s always best to head out with a more experienced guide, rather than relying on photos or descriptions. Look online for local mycology groups in your area and see if there are any mushroom hunts planned which you can join. Although these trips are a good chance to connect with likeminded fungi enthusiasts, initially be careful about blatantly stating your intentions if you’re only interested in psychedelic species, at least until you have a good feel for how your local mycology group feels about psychedelic foraging!   

Psilocybe Mexicana Cultivation

The cultivation of P. mexicana, P. cubensis and P. caerulescens were all first studied around the same time in the late 1950s by Roger Heim and his colleagues in France. In initial experiments, Psilocybe cubensis outperformed other species due to its fast colonisation and ability to easily produce large mushrooms, and is a likely reason why this species is now the go-to fungal favorite of home growers the world over. However P. mexicana is also grown to a lesser extent today, usually for its sclerotia, though mushroom production is also possible with a little extra care.

Early experiments with laboratory cultivated strains of P. mexicana suggested that sclerotia production is favored by dark, nutrient-rich conditions whereas mushroom production was favored by when cultures were exposed to daylight in growth media that are less nutrient rich. From a biological perspective this makes sense; given the function of sclerotia to act as a survival structure, high nutrients would create conditions that promote building up supplies for times when conditions might not be so abundant. By contrast, in low nutrient conditions, mushrooms and their resultant spores would give the organism a chance to escape their poor growing conditions for a new start somewhere more favorable. Although this hasn’t been proven scientifically, many anecdotal reports from home growers state that once a P. mexicana grow has started producing sclerotia, future mushroom production is less likely. 

The little scientifically documented work on cultivation carried out in the late 1950s suggested that fermented, washed and sterilised straw could be used to grow both mushrooms and sclerotia, with a layer of sterile sand added to jars to improve drainage. Since then hobby growers have had success by typically using a mix of coir and vermiculite, sometimes adding manure or straw, in a similar way to P. cubensis. For those wanting to try and cultivate mushrooms rather than sclerotia, it seems that low nutrients and ample light may be crucial factors for success. Consider bulking out your substrate with a high proportion of vermiculite, which lacks nutrients and can help dilute richer substrates like coir, manure or straw. It’s also important to note that Roger Heim’s initial cultivation studies on P. mexicana cultures taken from different wild locations found considerable variation in their ability to produce mushrooms, with some hardly producing any at all. Those hoping to grow P. mexicana mushrooms might have greater success gathering spores from multiple sources or vendors to increase the chances of success. 

For those of you happy to grow sclerotia alone, the technique is the same as producing P. cubensis grain—you can even do it with Uncle Ben’s tek! Although you can spawn to bulk, this typically isn’t necessary if you only want sclerotia, making this species the perfect “set-and-forget” project. Compared to P. cubensis, growing P. mexicana can take a little longer, coming in at two to three months minimum. Jars or bags containing sclerotia can be left for longer than the minimum time, and sclerotia inside will continue to grow, though extra care needs to be taken to ensure everything doesn’t dry out.      

Psilocybe Mexicana Potency

Photo by Alan Rockefeller

Despite the Dutch Ministry of Health stating that sclerotia are weaker than mushrooms, the truth in this claim depends on what you’re actually comparing. Sclerotia in general contain less water than mushrooms; around 75 percent compared to around 90 percent. On a fresh weight basis sclerotia may be actually more potent than many common psychedelic mushroom species, but this relationship switches once both the mushrooms and sclerotia have been properly dried due to the difference in moisture content.  

Although we don’t have direct measurements of potency for P. mexicana sclerotia, mushrooms themselves have been reported to contain a maximum of 0.25 percent psilocybin and 0.25 percent psilocin. On paper, this makes P. mexicana weaker in comparison to the more commonly grown P. cubensis, which are reported to contain a maximum of 1.3 percent psilocybin and 0.35 percent psilocin. However those who have tried both have reported P. mexicana mushrooms to have similar, or greater potency than P. cubensis depending on who you ask. In addition, sclerotia of P. mexicana are anecdotally considered to be of roughly equal potency to P. cubensis mushrooms.

A reason for all this confusion is likely due to the fact that magic mushrooms in general can vary greatly in potency depending on how they’re grown, so making comparisons between species is relatively difficult. In addition, few scientific studies exist on potency and subjective trip reports are notoriously difficult to interpret. Usually some reliability can be gained from the sheer number of anecdotal potency reports (such as the case for P. azurescens), but for P. mexicana it seems fewer people have tried them, or at the very least documented their experiences. Until better data comes along, our dosing advice would be to start slightly lower than you might for P. cubensis and see how you do: Remember that you can always take more, but you can’t take less! For those of you hoping to microdose with P. mexicana, just make sure you calibrate your dosage on a day when you don’t have any obligations, just in case! 

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