Dotted Stem Bolete

Description

The dotted stem bolete has a dark brown, suede-like cap up to 20 cm across, small orange-red pores and a yellow stem densely covered with brick-red dots. All damaged parts, especially the tubes and flesh, quickly turn blue, sometimes to dark navy or black. The smell is weak, the taste mild.

It grows from May to late autumn in broadleaved and coniferous forests, more often in the mountains than in the lowlands, under firs, beeches, hornbeams, spruces and oaks. The jonquil-yellow variety is very rare in Poland.

Red pores and blueing make it easy to confuse with other red-pored boletes, including poisonous or inedible ones. It has dots on the stem, not a net; if you are not sure, do not collect it.

Identification features

Cap

Diameter up to 20 cm; in young ones semicircular, then convex to spread out. Surface at first dry, suede-like, velvety, later smooth and bare. Colour dark brown (in descriptions also chestnut), sometimes with ochre flecks. Darkens when damaged.

Hymenophore (underside of the cap)

Tubes long, notched at the stem; in young fruiting bodies yellow to olive (in descriptions also yellow-green), in older ones rusty. Pores small, orange-red (yellow in young ones, rusty with age). When damaged, tubes and pores turn strongly blue, up to black.

Stem

Height 4-15 cm, thickness 2-5 cm; at first bulging, then club-shaped or barrel-shaped, solid. Yellow, very densely covered with brick-red, irregular dots or fibrils - not a net; in the upper part there are fewer dots and the stem is more yellow there.

Flesh

Yellow; when cut or damaged it quickly turns dark blue. Taste mild, smell weak. The raw flesh should not be tasted.

Spore print and spores

Spore print olive-brown. Spores elliptic-spindle-shaped, smooth; dimensions 13-18 × 5.5-6.5 µm.

Habitat and distribution

Ecology. A mycorrhizal fungus (ectomycorrhiza). The typical variety grows mainly under firs, hornbeams, beeches, spruces, pedunculate oak and linden; the jonquil-yellow variety under oaks and beeches. It often grows in the same places as the porcino.

Distribution. According to some descriptions known only in Europe and Japan; according to others also in North America (under the name N. luridiformis). Fairly common in Poland, much more frequent in the mountains than in the lowlands. The jonquil-yellow variety is very rare in Poland; Red list: E (endangered). Not legally protected (Dz.U. 2014 item 1408).

Fruiting. From May to late autumn (according to some descriptions summer and autumn).

What can it be confused with?

• Caloboletus calopus (bitter beech bolete) — Bitter and inedible. Young fruiting bodies are sometimes confused, because the two often grow together. The dotted stem bolete has red dots on the stem instead of a net, red tubes in older ones (instead of yellow) and a darker cap.
• Suillellus queletii (deceiving bolete) — Cap olive-brown, orange- or brick-red, pores orange, stem carmine-red at the base.
• Suillellus luridus (lurid bolete) — Stem with a distinct net with elongated meshes, instead of small red dots; prefers calcareous ground.
• Rubroboletus satanas (Satan's bolete) — Moderately poisonous; stem with a net, cap very pale, whitish.

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 name erythropus comes from the Greek words for "red" and "foot", which refers to the reddish stem.
• In Polish literature it was called, among others, "grzyb wilczy" (wolf mushroom), "czerwononóżka" and "pociec".
• For about 200 years the name Boletus erythropus was applied to this mushroom, until it was discovered that Persoon had probably described a different species (Suillellus queletii).
• The genus Neoboletus was separated in 2014 on the basis of genetic studies, which showed its distance from the genus Boletus.