Mottled Bolete

Description

The mottled bolete has a conical cap 6–12 cm across, dry and matt, slightly felty, and lightly tacky in wet weather. Its colour is variable, from olive-grey to dark brown. The underside consists of small white or cream pores that darken when damaged. The slender, whitish stem is covered with dark brown to black scabers, and may be greenish or blue-green at the base. The white flesh turns pink when cut, but only after a fairly long time.

It grows under birches, most often in damp places, especially on peat bogs, from July to October. In Poland it is not rare.

It is most easily confused with the brown birch bolete, which grows in drier spots and has a paler cap, in shades of brown only. In practice the two species are often not told apart. If you are not sure of the species, do not pick it and do not eat it.

Identification features

Cap

Diameter 6–12 cm; conical in young fruiting bodies, conical with a rounded tip in older ones. Surface smooth, matt, dry, slightly felty, slightly tacky in wet weather. Colour ranges from olive-grey through grey and grey-brown to dark brown.

Hymenophore (underside of the cap)

Tubes up to 25 mm long, deeply notched at the stipe, whitish to cream. Pores almost round, small, white or cream; they darken when damaged.

Stem

Height up to 18 cm, thickness up to 3.5 cm; solid, cylindrical, slender, often curved. Whitish, covered with numerous dark brown to black scabers (small scales). Sometimes greenish or blue-green at the base.

Flesh

White to whitish-cream, may be whitish-green at the base. Turns pink when cut, but only after a fairly long time. Taste and smell pleasant, mild. Do not taste the flesh for identification purposes.

Spore print and spores

Spore print brown to olive-brown. Spores elongated, 14–19 × 5–7 µm.

Habitat and distribution

Ecology. A terrestrial mycorrhizal fungus associated with birches (Betula). Grows mainly in damp places, especially on peat bogs.

Distribution. North America, Europe and Asia. In Europe it is distributed from the Mediterranean to Iceland and Svalbard, absent only from the south-east. In Poland it is not rare. It is not legally protected in Poland.

Fruiting. July to October.

What can it be confused with?

• Leccinum scabrum (brown birch bolete) — Also grows under birches, but in drier places; cap paler, in shades of brown only.
• Leccinum pseudoscabrum (hazel bolete) — Grows under hornbeams and hazel; flesh turns grey-violet when cut.
• Leccinum duriusculum (poplar bolete) — Grows under poplars; cap grey-brown, flesh first turns red and then black when cut.

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 was described in 1969 by the British mycologist Roy Watling.
• The name variicolor means “variously coloured” and refers to the great variability of the cap colour.
• It occurs on three continents: North America, Europe and Asia, and in Europe as far as Iceland and arctic Svalbard.
• In older Polish literature it was described as a variable form of the brown birch bolete.