Panaeolus cinctulus mushrooms

Panaeolus cinctulus: Identification, Effects & More

Everyone thought this shroom was poisonous—and then they realized it was magic.

DoubleBlind Mag

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Updated July 14, 2022

Mycologists have known about Panaeolus cinctulus mushroom for some time—but not always by the same name. This mushroom was first discovered in the 1860s growing in a grassy field in the quiet village of Apethorpe, England by renowned mycologists Miles Joseph Berkeley and Christopher Edmund Broome, who gave it the name Panaeolus subbalteatus

The mushroom was rediscovered in 1916 by American mycologist William Murril while working at the New York Botanical Garden. According to Muril’s report, a local field mushroom cultivator, along with four members of her household had eaten what we now know to be P. cinctulus by mistake “with nearly fatal results.” Thinking he had discovered a new poisonous mushroom, Murrill named this species Panaeolus venenosus (derived from the Latin word for poison), and recommended an immediate warning be sent out that “poisonous mushrooms may apparently develop from commercial spawn and that growers must be careful to eat or sell from their mushroom beds only the common mushroom with white cap and pink gills, Agaricus campester [sic].”

Around the same time, this mushroom gained the nickname “weed panaeolus”, due to the frequency with which P. cinctulus was found growing in mushroom beds, alongside cultivated edibles like Agaricus bisporus (button mushrooms) and Agaricus campestris (field mushrooms). Thanks to Murill’s panicked journal article, the name “poison panaeolus” may have also been used for a number of years. The different Latin names have now been gathered under P. cinctulus, but the old common name of weed panaeolus is still used, along with names like girdled panaeolus, banded mottlegill, and red caps—referring to different aspects of this mushroom’s appearance.

Panaeolus cinctulus mushrooms
Wikimedia Commons

Panaeolus cinctulus Effects

Despite its alarming history and association with so-called “poisonings,” no human deaths have ever been recorded from this mushroom. The few descriptions of accidental P. cinctulus ingestion result in symptoms that on the surface appear to be consistent with a magic mushroom experience. One record of such an event involved a hospital admission of a Scottish man and woman who reported nausea, difficulty carrying out work, as well as a “sharpening of the senses.”

Like other psychedelic mushrooms, P. cinctulus have been found to contain psilocybin, psilocin, and baeocystin. Though the subjective effects of magic mushrooms may be shaped by the relative concentrations of different alkaloids, you can expect that a trip on P. cinctulus will share many similar features, like those felt from a more commonly available species like Psilocybe cubensis. While some online trip reports might make claims of different subjective effects, given the powerful impact of set and setting in any psychedelic experience, it’s hard to separate the effects of different species, especially considering that no two mushroom trips are ever the same.

Read: Mushroom Dosage: What Is the Right Amount of Shrooms?

Panaeolus cinctulus Dose

The maximum known potency of P. cinctulus puts them at about half as strong as your average P. cubensis variety. However, like other psilocybin-containing mushroom species, the alkaloid content of P. cinctulus may vary between young and old mushrooms and between mushrooms picked in different regions. Given this variation in potency, some have found that a psychedelic experience brought on by a particularly strong batch of P. cinctulus might be more comparable to trip on a weaker variety of P. cubensis.

Panaeolus cinctulus gills
Wikimedia Commons

If you’re used to dosing with P. cubensis, a good starting point for consuming P. cinctulus would be at least the same amount as your preferred P. cubensis dose. If you’re not feeling the familiar effects after an hour or so, you can always take a little more and see how you go from there. It’s best to proceed with caution when trying out any new species of psychedelic mushroom for the first time and understand that when it comes to finding a comfortable dosage, a few weaker dose-finding trips might be preferable to one that’s far too intense.

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Panaeolus cinctulus Identification

The caps of P. cinctulus mushrooms can grow up to around two inches in diameter when fully mature, turning from dome-shaped (hemispherical or convex) to flat as they grow in size. The color of the cap changes as the mushroom dries out (hygrophanous), with moist caps looking reddish-brown and dry caps taking on a creamy white appearance. The older Latin name for this mushroom translates to “somewhat (sub) girdled (balteat)” and refers to the darker band found around the edge of fresher caps. This zonate band can help identify the mushroom—but remember that this feature may become less obvious as the cap begins to dry. 

Underneath the cap, the densely packed gills are attached to the stem either narrowly (adnexed) or broadly (adnexed). The gills start cream-colored in young specimens but mature through brown to sooty black as the spores develop. The hollow stem of P. cinctulus lacks any veil remnants and can reach up to four inches in height. The stem is a similar color to the cap and exhibits the same hygrophanous characteristics, though it also has a white powdery (pruinose) or fibrous (fibrillose) coating. 

 panaeolus cinctulus mushrooms
Mushroom Observer

Some foragers have found small blue-green sclerotia growing in between the mycelium under where P. cinctulus mushrooms appear, but reports of this finding are incredibly rare. It may be that those out hunting for P. cinctulus are simply picking the mushrooms but ignoring the small sclerotia lying just below the surface. Another possibility is that the name P. cinctulus might hide a number of similar species including those that do produce sclerotia and those that do not.›

Panaeolus cinctulus Bruising

Many experienced magic mushroom foragers state that the typical bluing reaction, found in both the mycelium and fruiting bodies, is less common in P. cinctulus. This bluing feature is so rare that early studies of this species claimed it didn’t bruise blue at all. Experienced foragers claim this rare blue staining is most likely observed in the mushroom stems or in their sclerotia, with blue staining caps the rarest of all.

Panaeolus cinctulus Spore Print

Unlike most Psilocybe species which have a purplish-brown spore print, the spores of P. cinctulus collect to form a jet black print. Almost all mushrooms in the genus Panaeolus have this same black spore print, except for the dark brown spores of Panaeolus foenisecii.

Panaeolus cinctulus Habitat

Though renowned for growing in the same substrate as edible mushrooms on commercial farms, we wouldn’t recommend asking your local farmer if you can have a browse of their beds. Luckily P. cinctulus also grows in the wild on compost piles, lawns that are rich in fertilizer, and very occasionally on the dung of animals such as horses. Foragers may find these mushrooms growing alone or in large patches, either as many single mushrooms or in little clumps.

panaeolus cinctulus mushrooms
Mushroom Observer

Where do Panaeolus cinctulus grow?

P. cinctulus is a cosmopolitan species, meaning that it grows all around the world. It has been found in the USA in all 50 states and every continent except Antarctica. Due to its wide distribution, the origins of this mushroom are uncertain—a factor which may have been further confused by commercial edible mushroom cultivators shipping spawn contaminated with P. cinctulus around the world.

Panaeolus cinctulus Season

Foragers are in for a treat: P. cinctulus season runs from spring to early fall, making it a popular magic mushroom to hunt for over the summer months. The mushroom grows abundantly after rain. However, it’s important to always check laws in your region before foraging for psilocybin mushrooms; these naturally-occurring psychedelics are decriminalized in some places, but certainly not all. Possession of psilocybin mushrooms remains illegal in many countries.

Panaeolus cinctulus Look-alikes

P. cinctulus is a little brown mushroom. As such, it’s always important to double-check your identification of this mushroom before consuming it: There are a lot of little brown mushrooms out there. One mushroom that is sometimes mistaken for P. cinctulus is Panaeolus foenisecii, which also grows on lawns. Though they don’t grow as large, P. foenisecii can easily be mistaken for less mature P. cinctulus mushrooms. To tell these two apart, key distinguishing features include lighter stems and a dark brown (not black) spore print. There have been some reports of people becoming sick after eating P. foenisecii, so if in doubt, avoid eating.

Panaeolus foenisecii
Panaeolus foenisecii | Mushroom Observer

Another lookalike is Panaeolus papilionaceus, which grows in the same habitat, but can be distinguished by partial veil fragments around the edge of the cap that look frilly or like small teeth. This species is considered inedible and does not contain psilocybin. Compared to P. cinctulus this mushroom also doesn’t show as obvious a color change depending on its moisture content.

Read: How to Grow Mushrooms

How To Grow Panaeolus cinctulus

Like many other Panaeolus species, P. cinctulus are considered challenging to grow compared to easier to cultivate species like P. cubensis. Despite this, dedicated growers have successfully grown the mycelium on agar, liquid culture, grain, and PF tek cakes. Bulk substrates typically include some horse manure or straw to mimic the natural environment where P. cinctulus are typically found. Those growing outdoors have had some success adding their spawn to patches rich in manure and straw to produce seasonal flushes of P. cinctulus.

P. cinctulus have also been occasionally documented to produce small sclerotia, nicknamed “blue pearls” by cultivators. This phenomenon was first observed on agar in a cultivation experiment in the 1930s, where they were first mistaken for contamination. In recent years, cultivators have had some successes reproducing these sclerotia, though many have found the yield to be too low to be worth the effort. Will future attempts to grow these blue pearls always be destined to be a waste of effort? Are there multiple species hiding behind this single name? Or is there some secret substrate recipe for P. cinctulus sclerotia waiting to be discovered? Only time will tell.

Note: Cultivating and foraging psilocybin mushrooms remains illegal in many places around the world. Always check the laws in your region before proceeding.  

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DoubleBlind is a trusted resource for news, evidence-based education, and reporting on psychedelics. We work with leading medical professionals, scientific researchers, journalists, mycologists, indigenous stewards, and cultural pioneers. Read about our editorial policy and fact-checking process here.

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