Peppery Bolete

Description

The peppery bolete is a small bolete-type mushroom with an orange-brown, smooth cap 2–5 cm, slimy in wet weather. Under the cap it has rusty-brown, angular pores, and the flesh in the stem is yellow. The very sharp, burning taste of the flesh is characteristic.

It grows in summer and autumn in coniferous and mixed forests, often under pines, spruces and birches, usually near fly agarics. In Poland it is fairly common.

It can be confused with boletes of the genus Suillus, e.g. the variegated bolete, which is larger and does not burn the tongue. It is not described as a strongly poisonous mushroom, but in Poland it is classed as inedible because of its sharp taste.

Identification features

Cap

Diameter 2–5 cm, exceptionally up to 7 cm (descriptions also give 1.6–9 cm). Cushion-shaped when young, then somewhat flattened. Cuticle smooth, orange-brown (orange-buff), slimy in wet weather, shiny in dry weather; may be grooved and crack with age.

Hymenophore (underside of the cap)

Tubes fairly short (3–10 mm), attached or slightly running down the stem, rusty brown. Pores large, angular, with uneven edges (about 0.5–2 mm), from yellowish to brick-brown, copper-coloured; they turn brown when damaged. In var. hypochryseus the tubes and pores are yellow.

Stem

Height 2–6 cm (descriptions also give 4–9.5 cm), thickness 0.4–1 cm (descriptions also give 0.6–1.2 cm). Cylindrical, of equal thickness or slightly narrowed towards the bottom, solid, sometimes bent. Colour like the cap or paler; yellowish at the base, with yellow mycelium. No ring.

Flesh

Cream in the cap, yellow to lemon-yellow in the stem, sometimes with a reddish tint, turning purple-brown with age. Smell weak or absent. Taste sharp, burning (peppery) — a feature of the species; it is not recommended to taste it.

Spore print and spores

Spore print brown to cinnamon. Spores smooth, spindle-shaped. Size approx. 7–12 × 3–5 µm (descriptions give different ranges).

Habitat and distribution

Ecology. Terrestrial. Formerly regarded as mycorrhizal, but this has not been confirmed in mycorrhiza synthesis or isotope studies; now suspected of parasitising the mycorrhiza of the fly agaric (Amanita muscaria), with which it usually grows. Associated with coniferous and mixed forests (juniper, fir, spruce, pine, birch, beech), often on sandy soils. The fruiting bodies may be attacked by the mould Sepedonium chalcipori.

Distribution. On all continents except Antarctica; fairly common in Central Europe, including Poland. Introduced to, among others, Brazil, Chile and Tasmania. Not legally protected in Poland.

Fruiting. In Poland in summer and autumn; in Europe from August to November.

What can it be confused with?

• Suillus variegatus (variegated bolete) — Distinctly larger, without a burning taste.
• Suillus bovinus (Jersey cow bolete) — sometimes confused — Detailed differences — no data.
• Boletinus cavipes (hollow bolete) — Stem hollow, ring fading; taste slightly bitter, not as burning.
• Chalciporus rubinus — Pores red, stem covered with red dots.
• Chalciporus piperatoides, Chalciporus rubinellus — North American species: the first turns blue when damaged and is less peppery, the second has brighter colours and completely red tubes.

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 species name piperatus means "peppery" in Latin.
• In 1908 it became the type species of the genus Chalciporus, which is an early branch of the Boletaceae and includes probably parasitic fungi.
• The substance chalciporone is responsible for the bitter taste of the fruiting bodies.
• It was formerly regarded as a mycorrhizal fungus; it is now suspected of parasitising the mycorrhiza of the fly agaric.