Bitter bolete

Tylopilus felleus

Inedible

Bitter bolete — Photo: Holger Krisp, CC BY, Wikimedia Commons

Never identify a mushroom from a photo alone. If in doubt, leave it. In case of poisoning call 112 (103 in Ukraine) at once.

About

The Bitter bolete, or felleus, disappoints many mushroom pickers: from a distance, it closely resembles the porcini or the birch bolete, and wormy specimens are rare, making the mushroom appear perfect. In the Carpathians, it is common in spruce and mixed forests, on acidic soils, among moss, near stumps, and grows from June to October.

The cap is 4–15 cm, light nut-brown or brown, dry, and velvety. The tubes of a young mushroom are white, then pink, and in an old one, dirty pink; the flesh is white and may turn slightly pink when cut. The most reliable feature is the stem: it is covered with a distinct dark brown mesh. If you touch the flesh with the tip of your tongue and immediately spit it out, you will feel a strong bitterness, but it is not advisable to do this with unfamiliar mushrooms.

The Bitter bolete is not poisonous, but it is inedible: the bitterness does not disappear during boiling, frying, or pickling; on the contrary, it intensifies. One such mushroom in a pot makes the entire dish bitter.

The Bitter bolete is most often confused with the porcini, which never has pink tubes, and the mesh on its stem is light. The birch bolete has dark scales on its stem, not a mesh. The king bolete differs with yellowish tubes that turn blue when pressed.

This species does not live in the Ukrainian Carpathians today — you can see it in other Carpathian countries.

Where in the Carpathians

fewermore5 records in the Carpathians

The map shows where naturalists recorded the species (GBIF, CC0 and CC BY records), not every place it lives. The Ukrainian Carpathians are less studied, so a blank area does not mean the species is absent.

Countries: Poland · Romania · Slovakia
Mountain ranges: Harghita and Gurghiu Mountains, Silesian Beskids
Altitude belts: Foothills (below 600 m) · Conifer forests (1200–1600 m)

When to see it

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Sightings

From naturalists’ observations in the Carpathians (iNaturalist, research grade): the darker the cell, the more often the species is seen that month.

Safety

Not poisonous, but very bitter and spoils dishes. Check the tubes and stem of every 'porcini'.

Look-alikes — how to tell them apart

PorciniBoletus edulisEdible

The tubes are white, yellowish, or olive, never pink; the mesh on the stem is light; the flesh is not bitter.

Birch boleteLeccinum scabrumEdible

Has dark scales on the stem, not a mesh; grows only near birch trees.

Protection and rules

Not protected. It is not advisable to destroy mushrooms in the forest: they are needed by the forest and animals.

FAQ

Is the Bitter bolete poisonous?

No, it is not poisonous, but it is inedible due to the strong bitterness that only intensifies during cooking.

How to distinguish the Bitter bolete from the porcini?

The Bitter bolete has pink tubes, and the stem has a dark brown mesh. The porcini has white or olive tubes, and the mesh is light.

Similar species

EdiblePorciniBoletus edulisHow to tell: The tubes are white, yellowish, or olive, never pink; the mesh on the stem is light; the flesh is not bitter.

EdibleBirch boleteLeccinum scabrumHow to tell: Has dark scales on the stem, not a mesh; grows only near birch trees.

EdibleBay boleteImleria badiaA chestnut mushroom of coniferous forests, whose tubes turn blue upon contact. A good edible mushroom; season – from July to November.

Where to meet it

Mountain ranges: In other countries: 🇷🇴 Harghita and Gurghiu Mountains, 🇵🇱 Silesian Beskids

Trails and peaks near which naturalists recorded the species (GBIF, iNaturalist), matched by altitude and habitat. Sightings are not guaranteed.

Sources

GBIF · iNaturalist · Wikidata · Distribution data: GBIF.org (CC0 and CC BY records), iNaturalist; names and identifiers: Wikidata (CC0). Text: Karpaty.rocks, checked 09.11.2026.