liberty cap mushroom

Liberty Caps Are Among the Most Potent Magic Mushrooms

Psilocybe Cubensis Isn’t the Only Magic Mushroom Out There—Here’s What You Should Know about Its Cousin, Psilocybe Semilanceata (AKA Liberty Caps)

DoubleBlind Mag

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Updated May 22, 2024

Known by numerous names—Liberty Caps, Blue Legs, Pixie Caps, Witches Hats—Psilocybe semilanceata is an unassuming innocent-looking mushroom, often happily growing next to many similar species, including Panaeolus spp. and Protostropharia semiglobata. Like Psilocybe cubensis, Liberty Caps grow in fields and pastures, but prefer the cold of temperate climates. Found growing in fall and spring, these delicate-looking, slender mushrooms are among the most potent Psilocybe species.

After Psilocybe cubensis, P. semilanceata is perhaps one of the best known of the Psilocybe genus. Most often referred to as “Liberty Caps,” this species has a fascinating history and is responsible for the first reported European magic mushroom trip in 1799. P. semilanceata became popular in Europe in the 1960s for its psychoactive properties after French botanist Roger Heim and Albert Hofmann identified it as containing psilocybin. In 2009, P. similanceata became the type species of the genus Psilocybe – the species that defines the genus – after a reassessment of both Deconica and Psilocybe. Psilocybe was nearly renamed, but due to the legal implications, the blue bruising species retained the name Psilocybe.

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Mycologist Gastón Guzmán, author of the 1983 monograph The Genus Psilocybe, considered P. semilanceata to be the world’s most widespread Psilocybe species. Assumed to be native to Europe, it grows throughout many parts of the temperate northern and southern hemispheres.

Magic Mushrooms UK: Europe’s First Reported Psilocybe Trip

In 1799, an impoverished family who had been picking fungi in London’s St. James’s Green Park prepared a meal with the mushrooms they had gathered. Not long after eating their meal, the father and his four children experienced symptoms typical of psilocybin: dilated pupils, spontaneous laughter, and vertigo. The father of the family even at one point believed he was dying. That same year, chemist Augustus Everard Brande wrote about the family’s experience when he published an account called “On A Poisonous Species of Agaric” in the London Medical and Physical Journal.  

The suspected mushroom can be identified as P. semilanceata from the illustrations of James Sowerby’s 1803 book Coloured Figures of English Fungi or Mushrooms. The book also includes a brief mention of Brande’s article, in which he writes that the Liberty Caps “nearly proved fatal to a poor family in Piccadilly, London, who were so indiscreet as to stew a quantity (found in St. James’s Green Park) for breakfast.” Sowerby listed the mushroom as Agaricus glutinosus (described by Moses Ashley Curtis in 1780). The description and illustration include the common lookalike Protostropharia semiglobata.

vintage liberty cap illustration
Illustration from James Sowerby’s 1803 book Coloured Figures of English Fungi or Mushrooms

In 1963, chemist Albert Hofmann, mycologist Roger Heim, and lab technician Hans Tscherter reported the presence of Psilocybin in P. semilanceata, the first species from Europe reported to contain psilocybin. Hofmann and Heim had begun studying P. semilanceata based on information about the Sowerby book from a letter written by mycologist Rolf Singer to banker and amateur mycologist R. Gordon Wasson. Heim and Hofmann had worked with Wasson to identify the mushrooms, and their active ingredient, used in the ceremony with curandera Maria Sabina in Oaxaca, Mexico, which became the subject of Wasson’s 1958 LIFE Magazine article “Seeking the Magic Mushroom.”

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During the 1960s and 1970s, resourceful university students and mushroom seekers learned that they didn’t have to travel to Mexico to find psilocybin; that magic mushrooms grew in their own countries. The growing knowledge about where to find P. semilanceata led to increasing numbers of counterculture youth wandering grasslands and pastures of the United States, Canada, and Europe, head down, bum in the air searching for the Liberty Cap – the “psilocybin stoop!”.

Liberty Caps in Literature

The name “Liberty Cap” seems appropriate, certainly regarding the states of mind that a strong psilocybin experience can conjure, not to mention the resulting philosophies. But the name has a different, but no less revolutionary, origin. P. semilanceata takes its common name from the Phrygian cap, also known as the “Liberty Cap,” which it resembles.

The Latin word pileus means “cap,” and in mushroom taxonomy, it refers to the “cap” of a mushroom. In the late Roman Empire, free men (non-slaves) wore a soft felted cap called a pileus. When a slave was given their freedom, they were given a pileus as a symbol of their liberty and right to vote (if male). 

1839 U.S. Gobrecht dollar coin
Obverse of 1839 United States Gobrecht dollar coin, the first of the “Seated Liberty” type | Wikimedia Commons

The identification of the pileus with the Phrygian cap began in the 18th century when the pileus was confused with the Phrygian cap; the Phrygian cap became a symbol of freedom and liberty as the “bonnet rouge” of the French Revolution. Referring to P. semilanceata as “Liberty caps” began with the 18th-century practice of placing Phrygian caps on “Liberty poles,” closely resembling the mushroom. In 1812, British poet Robert Southey, with fellow poet Samuel Taylor Coleridge, published a  two-volume book Omniana, which included the following observation on the “Cap of Liberty”:

“There is a common fungus, which so exactly represents the pole and cap of liberty, that it seems offered by nature herself as the appropriate emblem of Gallic republicanism—mushroom patriots, with a mushroom cap of liberty.”

Quite possibly the earliest usage in a mushroom guide was in the 1894 book Edible and Poisonous Mushrooms by Mordecai Cooke (also known for The Seven Sisters of Sleep, the book on narcotics that inspired Alice in Wonderland by Lewis Carroll). The text refers to P. semilanceata as the “cap of liberty,” the phrasing used in Omniana.

Liberty Cap Mushroom: What Does it Look Like? 

Psilocybe semilanceata is a tall thin field mushroom. The cap is quite distinctive, with a pronounced papilla on top of a tall and slender cap. The stem is long and thin, enough to raise the cap above the grass to distribute its spores. Although delicate looking, these are tough mushrooms, and a common identification test is to twist the stem around your little finger to see if the stem breaks. In most cases, a Panaeolus or Conocybe stem will readily break, but Liberty Caps are very fibrous and should not snap.

Liberty caps have a cap that is approximately 5–25 mm (0.2–1.0 in) in diameter and a height of 5-10cm (2-4 in). The cap can vary in shape from sharply conical to bell-shaped.  A distinctive feature is their prominent papilla (the nipple-shaped top of the cap). At maturity, the cap margin is straight and can become slightly curled upwards. When moist, radial grooves (striations) can be seen on the cap that corresponds to the positions of the gills underneath. 

A feature of Psilocybe spp. is their hygrophanous cap, and this is no different with P. semilanceata. The cap has a gelatinous layer called a separable pellicle; as this dries out, the cap can take on different colours depending on the moisture present. When the cap is moist, it can be pale brown to dark chestnut brown, often with a green-blue tinge. The pellicle can be used as an identifying feature by gently breaking the cap and bending it back to reveal the layer. When the cap is dry, it becomes much paler, a light yellow-brown color, and the pellicle is no longer peelable

mushroom gills
The cap has a gelatinous layer called a separable pellicle | Courtesy of Caine Barlow

The gills are narrow and moderately crowded together, initially pale brown, but becoming dark grey to purple-brown as the spores mature. Their attachment to the stem is narrowly adnexed, almost free. P. semilanceata are reported to have a thin cobweb-like partial veil, but these are rarely visible. The partial veil can leave an annular zone on the stem, to which spores stick, leaving a darkened ring around the stem. The stem is slender, off-white turning yellow-brown, 45–140 mm (1.8–5.5 in) in length, and 1–3.5 mm (0.04–0.14 in) thick, usually equal thickness becoming slightly thicker towards the base.

An important diagnostic feature of the genus Psilocybe is the blue bruising; Liberty Caps do not bruise as readily as other Psilocybe spp., but will show some bruising on the base of their stem, hence the name “Blue Legs.”  As with other Psilocybe spp. they have a farinaceous, flour or starch-like odor.

Liberty Caps are a mushroom with many names

Psilocybe semilanceata was named Agaricus semilanceatus by Elias Magnus Fries, who wrote the first formal description in 1838 for his book Epicrisis Systematis Mycologici. The species was moved to Psilocybe in 1871 by Paul Kummer, while reviewing Fries’s classifications. “Agaricus” had been used as a broad umbrella name, so Kummer, revising Fries classification, moved many species to their own genus. 

The Genus name “Psilocybe” is derived from the Ancient Greek psilos (ψιλός), which means “smooth” or “bare,” and the Byzantine Greek kubê (κύβη), which means “head.”  The species name “semilanceata” means half spear-shaped, from the shape of the pileus—the Latin semi (“half” or “somewhat”) and lanceata, from lanceolatus, meaning “spear-shaped”.

Sometimes how a species is classified changes, resulting in the name of a species changing as well. The first person, or people, to describe a species are always associated with the name given, with the year it was renamed. In the case of Liberty caps, the formal name is: Psilocybe semilanceata (Fr.) P.Kumm. (1871). “Fr.” for Elias Magnus Fries, who first described the species, and “P.Kumm” for Paul Kummer, who assigned the species to Psilocybe in 1871.

Synonymity can be quite common among formal descriptions of fungi. Mycologists would often describe and name a species unaware that others had done the same in other locations – upon revision these would be found, and formally associated as the same species. Psilocybe semilanceata is synonymous with Agaricus semilanceatus Fr. (1838), Geophila semilanceata (Fr.) Quél. (1886),and Panaeolus semilanceatus (Fr.) J.E.Lange (1936). If you ever read old field guides (there are many freely available to download on, it is helpful to keep in mind that the species mentioned may have since been renamed.  

In the late 2000s the genus Psilocybe almost lost its name. Psilocybe montana was recognized as the type species of the genus—the type species being the oldest known described species of a genus. Psilocybe contained many non-bruising species, and genetic studies revealed there were two different groups that needed to be separated. Psilocybe montana being the type species meant that all the psilocybin-containing species would have to be moved to a new genus. Given the legal implications of renaming the genus Psilocybe, the unusual decision was made to make P. semilanceata the type species, moving P. montana to Deconica to become Deconica montana.

Liberty Caps: Where are they found?

liberty cap mushrooms
Courtesy of Caine Barlow

Psilocybe semilanceata is a temperate and sub-alpine species. It can be found growing in both autumn and spring; in the northern hemisphere, growing in August to November and then May to June. In the southern hemisphere, it grows from April to May and then September to October. It tends to favor oceanic climates.

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Liberty caps grow throughout Europe, where it is assumed to be an endemic species. It is thought that they were introduced to other countries by the movement of livestock. It now occurs throughout the temperate regions of the northern and southern hemispheres. In the US and Canada, P. semilanceata occurs along the west coast, from British Columbia to California, and in some locations on the East Coast, from Nova Scotia to Newfoundland. In the Southern Hemisphere, P. semilanceata grows in Tasmania, south-east Australia, New Zealand, Chile, Argentina, and South Africa.

Psilocybe semilanceata is found amongst grass growing in rich soil in temperate meadows. The mushrooms are often scattered, but in rich soil can be found in dense groups, mainly when growing in fields near farmyards, or well-manured pastures. Liberty Caps are spread by animals and humans, either by foot traffic or dung. Although it does not typically grow directly on the dug, it is often found in pastures that have been fertilized with sheep, cow, or horse manure.

Psilocybe semilanceata: How Strong are They? 

liberty cap mushrooms
Courtesy of Caine Barlow

Most Psilocybe species will bruise a variety of shades of blue or blue-green when damaged, but in the case of P. semilanceata, they only tend to bruise a small amount at the base of their stem. Given their tall thin stature, you would probably pass on these given a familiarity with other species such as Psilocybe cubensis. To look at, you wouldn’t think they are very potent, but by the percentage of dry weight, they are more potent than P. cubensis.

Psilocybe semilanceata has been analyzed several times with variations in results. Tjakko Stijve and Thom Kuyper, in 1985 analysing a single specimen, found a concentration of psilocybin of 1.7 percent dry weight, with a concentration of baeocystin at 0.36 percent. In 1993, Gartz reported P. semilanceata having an average of 1.0 percent psilocybin by dry weight, ranging from 0.2-2.37 percent psilocybin. Analyzing specimens from the Pacific Northwest, Michael Beug and Jeremy Bigwood found psilocybin concentrations ranging from 0.62-1.28 percent, with an average of 1 percent. Psilocybe cubensis contain psilocin and psilocybin at 0.14-0.42 percent and 0.37-1.30 percent, respectively. 

Psilocybe semilanceata contain significantly more psilocybin than psilocin (psilocybin being more stable, deteriorating more slowly than psilocin) so that after a few months of storage in a cool dark environment, the mushrooms tend to retain most of their original potency. The main issue with P. semilanceata is that they dry to a tiny dry, thin mushroom; therefore, you need to collect a lot for a dose.  

How to find Liberty Caps

liberty cap mushroom
Courtesy of Caine Barlow

Psilocybe semilanceata is very difficult to cultivate, so the primary way of obtaining mushrooms of the species is to forage for them. The best way to start is to get to know your target species, learn the description, their habitat, and the timing of the seasons. If you live in areas where they are known to grow, fields, meadows, and lawns are the best places to look for Liberty Caps, especially if livestock have been present.

It is essential to know the lookalike species—species that may be confused with your target species. The most common lookalike species is Protostropharia semiglobata, various Panaeolus spp, Conocybe spp, and possibly Deconica spp. There are poisonous Psathyrella species that can easily be misidentified as Liberty Caps. Given the worldwide distribution of P. semilanceata, there will be different lookalike species on each respective continent and region. For example, in Europe, there is the poisonous species Cortinarius rubellus that has been confused for P. semilanceata, the consumption of which may result in kidney failure.  
When foraging, be sure to take a field guide for your area, and have a couple of forums handy on your phone. Shroomery has the “Mushrooms hunting and identification” subforum. The iNaturalist app is also very useful and can provide identifications when photos of the mushrooms are uploaded. There are numerous Facebook groups, as well, so you can join one local to the area where you are foraging, and members will be aware of local lookalikes. Check all the mushrooms as you collect them; try to avoid picking those that don’t fit the description. It is best to not trespass: Always seek the permission of the landowner; the gift of a bottle of wine or six-pack of beer can go a long way and may provide extra advice. Also, keep in mind, being found in possession of psilocybin-containing mushrooms is illegal in most parts of the world.

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