Orange Birch Bolete

Description

The orange birch bolete has a brick-orange or orange-yellow cap 5-15 cm across, cushion-shaped, slightly downy, with membranous remnants of skin at the margin. Underneath are tubes, whitish to greyish. The slender stem is white or light grey and covered with small black scabers, a feature of the whole genus of scaber stalks. When cut, the flesh turns pink-grey-violet, and at the bottom of the stem greenish-bluish.

It grows from June to October exclusively under or near birches, in forests and on heaths, singly or in groups. It is common in Poland.

It is most easily confused with the red-capped scaber stalk, which has a brighter cap, pale, later red-brown scabers and grows under aspen. Still, collect only specimens you are sure are a scaber stalk (tubes, scabers on the stem, birch).

Identification features

Cap

Diameter 5-15 cm, cushion-shaped convex, usually downy and rough, felty; colour brick-orange or orange-yellow (in descriptions also from tan, through yellow-orange and ochre, to brick-red). At the margin membranous remnants of the overhanging skin.

Hymenophore (underside of the cap)

Poroid; tubes 8-22 mm long, whitish with a grey tinge, yellowish-white to brown-grey, purplish to greyish when damaged. Pores about 0.5 mm, grey-white to grey-ochre, turning brown when damaged. Attachment to the stem - no data.

Stem

Height 6-15 cm, thickness 1-3 cm (according to some descriptions up to 3.5 cm), firm, slender. Surface white or light grey, covered with small black scabers that turn brown in older specimens (according to some descriptions the scabers are greyish to blackish, less often whitish).

Flesh

White to pinkish; when cut it turns pink-grey-violet to grey-brown, in the lower part of the stem greenish-bluish. Taste and smell - no data; the raw flesh should not be tasted.

Spore print and spores

Spore print brownish (according to some descriptions yellow-brown to olive). Spores smooth, elliptic-spindle-shaped, (9-)11.5-16.5 × 3.5-5 µm (descriptions give different ranges).

Habitat and distribution

Ecology. A mycorrhizal fungus (ectomycorrhiza), exclusively with birch (Betula), in forests and on heaths, on sandy, slightly acid loamy soils. Grows singly or in groups.

Distribution. North America, Europe and Asia; in Europe widespread, from Scandinavia to Iceland. Common in Poland. On the red lists of Germany and the Netherlands. Not legally protected in Poland.

Fruiting. From June to October; according to some descriptions from July or August to November.

What can it be confused with?

• Leccinum aurantiacum (red-capped scaber stalk) — Scabers on the stem at first whitish, then red-brown, never black; cap more intensely, brightly red; grows under aspen. The flesh also changes colour.
• Leccinum vulpinum (foxy bolete), Leccinum piceinum — Similar species; detailed differences - no data.

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

• It grows exclusively under or near birch, which is one of the best clues when identifying it.
• It has about 50 synonyms of its scientific name.
• After cooking the flesh turns black.
• It is on the red lists of threatened species in Germany and the Netherlands, although it is common in Poland.