Liberty Cap

Description

The liberty cap is a small meadow mushroom with a cap 1–2 cm across, conical or bell-shaped, usually with a distinct pointed peak at the top, resembling a Phrygian cap. The moist cap is olive-brown to light brown, slippery and striate, and turns straw-coloured when dry. The gills are at first light brown, then darken to purple-brown, and the stem is very thin, long, flexible and often wavy.

It grows from August to October in open areas: pastures, meadows, in grass and moss, often in damp places grazed by cows or sheep. In Poland it is not very common and is most often found on mountain meadows (hale) and in the foothills. It appears singly or in small groups of a few specimens.

It contains psychoactive substances (psilocybin), and possessing it in Poland is prohibited. It is also easy to confuse with other small brown grass mushrooms, among which are dangerously poisonous species. The characteristic features are dark gills, a sharp peak and a long, tough stem, but they are not enough for safe identification. Do not collect this mushroom for eating.

Identification features

Cap

Diameter 0.5–2.5 cm, height 0.6–2.2 cm; sharply conical to bell-shaped, usually with a distinct nipple at the top, and does not flatten out with age. The margin is at first inrolled, later straight or even slightly turned upwards. Hygrophanous: when moist from ochre and light brown to dark chestnut, darker at the centre, often with an olive or bluish-green tinge, radially striate; when dry pale straw to yellow-brown. The surface is smooth and slippery, sticky when wet thanks to a thin gelatinous skin that can be peeled off; once dry the skin turns whitish and can no longer be peeled.

Hymenophore (underside of the cap)

15–27 gills, broad, moderately crowded, narrowly attached to almost free. In young fruiting bodies light brown, darkening with age to dark grey to purple-brown (tobacco-brown), with a paler edge. The thin, cobweb-like veil disappears quickly; it sometimes leaves a ring zone on the stem darkened by spores.

Stem

Height 3–15 cm (descriptions give different ranges), thickness 1–3.5 mm; stipe thin, flexible, cylindrical, hollow, often wavy, usually slightly thicker towards the base. Colour pale ochre to yellow-brown, similar to the cap or slightly paler; surface smooth or longitudinally fibrous.

Flesh

Thin, membranous, beige when dry, grey-brown when moist. Smell and taste faint or mealy (descriptions differ). Damaged or ageing parts of the fruiting body may turn bluish. The flesh should not be tasted.

Spore print and spores

Spore print dark purple-brown. Spores oblong-ellipsoid to oval, 10.5–15 × 6.5–8.5 µm.

Habitat and distribution

Ecology. Saprotroph, feeding on dying grass roots, also associated with sedges in damp fields; it does not grow directly on dung. Prefers fertile, acidic soils, especially pastures fertilised with cow or sheep manure. May form sclerotia. In laboratory studies it inhibited the growth of other soil fungi and of the oomycete Phytophthora cinnamomi.

Distribution. Widespread in the temperate zone of the Northern Hemisphere, considered native to Europe; also recorded in North America (especially on the west coast), Chile, New Zealand and Australia (where it may have been introduced). In Poland not very common, mainly on mountain meadows (hale) and in the foothills. It is not under species protection in Poland.

Fruiting. From August to October; solitary or in groups of a few. In a warmer coastal climate it fruits until early winter.

What can it be confused with?

• Psilocybe strictipes — A slender meadow species that differs macroscopically in lacking a distinct nipple on the cap.
• Psilocybe pelliculosa — Practically indistinguishable in the field; differs in its smaller spores, 9–13 × 5–7 µm.
• Inocybe geophylla (white fibrecap) — Poisonous (muscarine). Whitish fruiting body with a silky cap, gills yellow-brown to pale greyish, spore print dull yellow-brown.
• Cortinarius rubellus (deadly webcap) — Highly poisonous species that damages the kidneys; a case of it being mistaken for the liberty cap that ended in a kidney transplant has been described. Identification requires certainty; one must not rely on resemblance.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• The English name "liberty cap" comes from the Phrygian cap of liberty, which the mushroom's cap resembles; the Latin name of that cap is pileus, today also the term for a mushroom cap.
• The earliest reliably described case of poisoning dates from 1799: a family in London ate mushrooms collected in Green Park, and the effects were described by the chemist Augustus Everard Brande.
• In 1963 Albert Hofmann detected about 0.25% psilocybin in dried specimens; this was the first description of the substance in a European mushroom.
• In 2009 the Nomenclature Committee for Fungi unanimously accepted a proposal to conserve the name Psilocybe with the liberty cap as its type species.