MycoNote

This English version was machine-translated from Ukrainian, so a few things may read a little off.

Sticky bolete (Suillus viscidus)
Photo: Dezidor · CC BY-SA 2.5 · source
Edible

Sticky boleteSuillus viscidus

Under review

Updated October 3, 2026

Passport

Edibility
Edible
Season
Aug — Oct
Hymenophore
Pored
Cap color
Grey
Size
Medium (5–15 cm)
Smell
Pleasant
Reviewed
Under review

Quick answers

Where to look?

Conifer forest, Mixed forest

When does it appear?

Aug — Oct

Active months: August, September, October.

How to recognize it? Three signs

  • Cap color: Grey, Olive, Brown
  • Cap shape: Convex
  • Smell: Pleasant

Fruiting season

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

August – October

Description

The sticky bolete, also known as the bluing larch bolete or gray bolete, and to science as Suillus viscidus, stands out clearly among the golden-brown Suillus crowd with its understated gray outfit. It's another faithful companion of larch: it forms mycorrhiza exclusively with these trees, so it turns up in the same places as Suillus clintonianus, in shelterbelts, parks and conifer plantations. It got its folk name "bluing" because its flesh slowly takes on a blue-green tint when cut.

In Ukraine, the sticky bolete is found wherever larch has been planted, throughout the country, from Polissia forestry districts to Carpathian plantations. Its fruiting season is shifted somewhat toward fall: it appears most actively from August to October, often fruiting right up to the first frosts, when other Suillus species have already faded out.

In terms of edibility, the sticky bolete is an edible mushroom, but its flavor is considered rather mediocre: its grayish, watery flesh falls short of its golden relatives. Some foragers note that in some people it can cause a mild laxative effect, so eat it in moderation and well cooked, and always peel the slimy skin off the cap first. It's perfectly fine as an addition to your basket, but it rarely becomes the main prize.

Cap

The cap of the sticky bolete reaches 4 to 10 centimeters across. When young it is convex and hemispherical, and with age it opens out to cushion-shaped and flat. The cap surface is very slimy and sticky, especially in wet weather, which is how the mushroom got its name. The coloring is subdued and variable, from dirty gray and gray-brown to olive-gray and pale clay, often with darker streaks or spots. The slimy skin peels off easily, revealing a paler surface.

Hymenophore

Under the cap is a layer of tubes with relatively large, angular and irregular pores, larger than in other Suillus species. They are dirty gray, grayish white or olive-tinged, which again sets this species apart from its golden-pored relatives. When pressed or damaged, the pores slowly take on a blue-green or brownish tint. In young mushrooms the pore surface is covered by a veil, the remains of which form a ring on the stem.

Stem

The stem of the sticky bolete is cylindrical, 4 to 8 centimeters tall, grayish white or pale gray. Near the top it has a noticeable slimy ring left by the veil; above it the surface is paler, and below it is covered with small grayish glandular dots. When touched, the stem may also slowly take on a bluish-green tint. There is no volva. The combination of gray tones, the ring and the link to larch reliably identifies this species.

Flesh

The flesh of the sticky bolete is whitish or grayish, fairly soft and watery, especially in mature mushrooms. Its characteristic trait, reflected in its folk name, is a slow color change in the air: when cut, the flesh gradually takes on a blue-green and sometimes pinkish-brown tint. The taste is mild, with no noticeable bitterness, but overall rather bland. Because of the watery texture and mediocre flavor, mostly young, firm specimens are chosen for the table.

Smell

The smell of the sticky bolete is weak and nondescript, typically mushroomy, with no sharp or unpleasant notes. Aroma is not a defining feature, so for identification rely on the gray slimy cap, the large grayish pores, the ring on the stem and growth next to larch.

›Scientific synonyms (3)

Suillus aeruginascens, Boletus aeruginascens, Ixocomus viscidus

Lookalikes

Mushrooms of the same genus and habitat — to study side by side and never mix up.

Related reading

Frequently asked questions

Is Sticky bolete edible or poisonous?
Sticky bolete is edible. Before eating any wild mushroom, always double-check current information in reliable sources and consult an expert.
Does Sticky bolete have gills or pores?
The spore-bearing surface (hymenophore) of Sticky bolete: pored.
What does the cap of Sticky bolete look like?
The cap of the sticky bolete reaches 4 to 10 centimeters across. When young it is convex and hemispherical, and with age it opens out to cushion-shaped and flat.
What does the stem of Sticky bolete look like?
The stem of the sticky bolete is cylindrical, 4 to 8 centimeters tall, grayish white or pale gray. Near the top it has a noticeable slimy ring left by the veil; above it the surface is paler, and below it is covered with small grayish…
What do Sticky bolete smell and taste like?
The smell of the sticky bolete is weak and nondescript, typically mushroomy, with no sharp or unpleasant notes. Taste: mild.
Where does Sticky bolete grow?
Typical habitats: Conifer forest, Mixed forest.
Which trees does Sticky bolete grow under?
Sticky bolete usually grows near: Larch.
When should you pick Sticky bolete?
It fruits in: August, September, October.
What can Sticky bolete be confused with?
Sticky bolete can be mistaken for: Suillus clintonianus, Larch bolete, Slippery jack, Hollow bolete. Study the distinguishing features carefully — detailed comparisons are in the “Lookalikes” section.
How do you cook Sticky bolete?
Sticky bolete can be fried, boiled, pickled and dried. Before cooking, it's recommended to boil it for 10–15 minutes and drain the water.
Can you dry Sticky bolete?
Yes, Sticky bolete is well suited to drying and freezing. Dried mushrooms keep their aroma and work well in soups, sauces and fillings.
What is the scientific name of Sticky bolete?
The Latin name is Suillus viscidus. It belongs to the genus Suillus, family Suillaceae.

Sources

  • [1]Вікіпедія (українська)
  • [2]Атлас грибів України, Зеров Д.К. (1979)
  • [3]MycoBank Database
  • [4]Index Fungorum
  • [5]GBIF
  • [6]iNaturalist Ukraine