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Grzybiarz is a mobile app for mushroom foragers. Its on-device AI helps you spot fruiting bodies in the leaf litter and suggests a species from a photo, and the app keeps a private map of your finds. Everything runs on your phone and works fully offline in the forest without signal.

Bitter BoleteTylopilus felleus

inedible

Bitter BoleteTylopilus felleus

Photo: (c) Shirley Zundell, some rights reserved (CC BY)

Habitat

pine forest

under spruce

mixed forest

deciduous forest

Season

from June to October

Season

Out of seasonOut of season. It usually grows from early July to early October.

Today · 22–28 Octout of season

how often reportedpeak

Season

Jun–Oct

Peak

Aug–Sep

Reports

192from Poland, few

Curve from 192 observations (iNaturalist, Poland), smoothed week by week. It shows when foragers most often report the species, not how much of it grows.

Species description

Inedible due to extreme bitterness, a single specimen can ruin an entire dish. Resembles a bolete but tubes turn pinkish with age and the stipe reticulum is dark brown.

Recognition features

confirm features

0 / 4

Whitish tubes that turn pink with age

Dark brown, coarse reticulum on the stipe

Extremely bitter (tongue-tip test)

Coniferous and mixed forests, acidic soils

Toxic look-alikesSpecies most often confused with this one.

King BoleteBoletus edulis

edible

Bay BoleteImleria badia

edible

Pine BoleteBoletus pinophilus

edible

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