Jack o'Lantern mushroom

Description

The jack-o'-lantern mushroom is a warmth-loving mushroom with a funnel-shaped, intensely orange cap (4–12 cm), with sharp gills running down the stem. The flesh is orange also inside the stem, and the gills of fresh fruiting bodies glow in the dark with a faint blue-green light.

It grows in clusters on stumps, at the base of trunks and on roots of deciduous trees, most often oaks, horse chestnuts and olives. In Poland it is very rare; the first site was found in 2020 on the Wyniosłość Giełczewska upland. It is common in southern Europe.

It is easily confused with chanterelles, but it has true, sharp gills and grows on wood. If you are not certain of the species, do not collect or eat it.

Identification features

Cap

Diameter 4–12 cm, funnel-shaped, intensely orange. No detailed description of the surface.

Hymenophore (underside of the cap)

True gills, sharp, thin, papery and flexible, distinctly decurrent down the stem, unforked, orange. Only the gills glow in the dark.

Stem

Length 3.5–9 cm, thickness 1–2 cm; colour orange, the same outside as inside (after peeling the skin). No information on a ring.

Flesh

Orange, the same colour outside and inside; does not change colour when cut or damaged. Smell slight. Taste not described — it must not be tasted; do not taste the flesh of this or any suspicious mushroom.

Spore print and spores

No data (spore print colour, spore shape and dimensions).

Habitat and distribution

Ecology. Saprotroph (warmth-loving) decomposing dead wood of deciduous trees: most often oaks, horse chestnuts and olives; the fruiting bodies grow on stumps, at the base of trunks and on roots, including underground ones. Grows in clusters.

Distribution. Europe, common in the south (Mediterranean countries, Iberian Peninsula, southern France), rare in Central Europe and limited to warmer sites; reported from, among others, Germany, Switzerland, Austria, the Czech Republic, Slovakia and Ukraine, also from the Western Cape Province in South Africa. In Poland very rare: first found in 2020 on the Wyniosłość Giełczewska upland. Not legally protected in Poland.

Fruiting. In southern Europe from July to October (summer and autumn). No data for Poland.

What can it be confused with?

• Cantharellus cibarius (chanterelle) and other chanterelles — The chanterelle has false gills in the form of blunt ridges, and after peeling the stem is paler than the skin; the jack-o'-lantern has true, sharp, flexible gills, flesh and stem of the same shade of orange, and grows on wood in clusters.
• Laetiporus (sulphur polypore) — Sometimes confused because of similar colour; detailed differences: no data.
• Omphalotus illudens, O. olivascens, O. japonicus — Related, also poisonous and bioluminescent species from North America and Asia (they contain the same illudins); they do not occur in Poland.

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 gills of fresh fruiting bodies glow in the dark with a blue-green light; only the hymenophore glows, and the mechanism is similar to the glow of fireflies (luciferase and luciferin).
• In Poland it was found for the first time only in 2020, on the Wyniosłość Giełczewska upland.
• It is a warmth-loving species, common mainly in southern Europe, and rare in Central Europe and limited to warmer sites.
• The exact function of bioluminescence in this species has not been established; studies have not confirmed that it serves to attract insects.