Liberty cap (Psilocybe semilanceata)

Names

In English it's the liberty cap. In Norwegian it's spiss fleinsopp, the name Norway's narcotics regulation lists alongside the Latin Psilocybe semilanceata.¹ It is, as a Norwegian medical journal put it in 2024, the only hallucinogenic mushroom that's common in Norway.⁶

What it looks like

The liberty cap is small and slender. Its cap is conical to bell-shaped with a distinctly pointed, nipple-like tip, and ranges from yellowish to brown on a thin stem.⁵ That pointed tip is the feature most people remember, but it isn't unique: several unrelated small brown grassland mushrooms look similar, some of them poisonous. This description is an overview, not an identification key.

Where and when it grows

Unlike Psilocybe cubensis, which grows on dung, the liberty cap is a grassland species that lives on decaying grass roots in pastures and meadows.^3,5 In Norway it's found on grassy sites in most of the country from mid-August to mid-October,² in nutrient-rich grassland as far north as Troms.⁴

Elsewhere it's widespread in the temperate Northern Hemisphere, especially in Europe. In the United States it's most often reported from the Pacific Northwest, and it's less common in the Southern Hemisphere.⁵

Chemistry and potency

Liberty caps typically carry high levels of psilocybin and baeocystin and comparatively little psilocin.³ They're also inconsistent. Researchers at the University of Oslo who analyzed wild Norwegian liberty caps in 1981 found psilocybin content varied about elevenfold between samples, with smaller mushrooms holding the highest concentration by weight. They described the species as "a potent hallucinogenic drug."² That kind of variation is why a mushroom's species, like a strain name, says little about what any particular mushroom contains.

History

The liberty cap has a long paper trail in Europe. A London family's poisoning in 1799, after eating mushrooms picked in Green Park, is often cited as the first reliable European account of its effects, and secondary sources credit Albert Hofmann, Roger Heim and Hans Tscherter with reporting psilocybin in the species in 1963, the first such finding in a European mushroom.⁵

In Norway, the 1981 Oslo study recorded that the species "has been used as a narcotic drug in Norway," and mapped where it grows across the country.² The university's pharmacy school later developed laboratory methods for measuring psilocybin in Norwegian liberty caps.⁹ When recreational use in Norway began isn't well documented. For the wider story, see our history of psilocybin.

Legal status in Norway

The mushrooms themselves are illegal in Norway, not just the chemicals in them. The narcotics regulation lists psilocybin, psilocin, Psilocybe cubensis, Psilocybe semilanceata and "mushrooms containing psilocybin or psilocin," and the mushroom entries explicitly cover spores and fresh, dried or processed mushrooms.¹ Norway's health information service states plainly that using and possessing spiss fleinsopp is prohibited and punishable under the penal code.⁴

In the United States, psilocybin and psilocin are Schedule I under federal law, and most states treat the mushrooms as illegal too. See our state-by-state legal map.

Lookalikes and the foraging warning

More on lookalikes and why bluing isn't a reliable test is on our species overview.

This page and the old NorShroom

From 2001 until about 2020, norshroom.org was NorShroom, a Norwegian-language psilocybin community, and its page on fleinsopp was among its most linked. Links to that old page now lead here. We aren't connected to the original NorShroom team; we kept this topic because the old links deserved somewhere useful to land. More on who runs Norshroom.