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Plant guide

Bitter Bolete.

Tylopilus felleus

Pronounced ty-lo-PI-lus FEL-le-us

Also known as Bitter Bolete

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Bitter Bolete
Photo by Shirley Zundell (CC BY) via iNaturalist

The Bitter Bolete is a common woodland fungus known for its striking resemblance to edible porcini mushrooms. It is easily identified by its bitter taste, which makes it inedible despite not being toxic. You will typically find these growing near deciduous or coniferous trees.

At a glance

Plant type
fungus
Water
Every 0 days
Hardiness
USDA 3 to 9
Bloom time
Summer to autumn

Care

This is a wild fungus that cannot be cultivated in a home garden setting. It relies on a symbiotic relationship with tree roots in forest ecosystems. Do not attempt to harvest for consumption due to its intense bitterness.

Watering
This species is a wild fungus and requires natural rainfall in forest habitats.
Feeding
Do not fertilize this wild fungus.
Pruning
Pruning is not applicable to wild fungi.
Repotting
This species cannot be repotted as it is a wild woodland fungus.
Temperature
5 to 25°C
Humidity
60 to 90%

Safety

People
It is not poisonous, but the intense bitterness makes it inedible.
Children
Keep children from eating this mushroom as it is not food and may cause digestive upset due to its extreme bitterness.
Contact allergens
No known contact allergies.
Airborne allergens
Spore release can cause respiratory irritation in sensitive individuals.
Edibility
This mushroom is not toxic but is extremely bitter and will ruin any dish it is added to.

How to identify it

  • Convex brown cap
  • Pinkish pore surface
  • Dark brown reticulated stalk
  • Extremely bitter taste
  • White flesh does not stain
Height
0.05 to 0.15m
Spread
0.05 to 0.15m
Leaves
deciduous
Flowers
0cm
Fruit
brown, tan, Summer to autumn

Problems to watch for

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    Growing it

    Propagation
    spores

    Look for this fungus in the leaf litter beneath mature trees where it helps cycle nutrients.

    Grows well with

    • Oak — This mushroom frequently forms mycorrhizal associations with oak trees.
    • Pine — It is commonly found growing in the soil near pine trees.
    • Spruce — Spruce forests provide the necessary habitat and root systems for this fungus.

    Similar species

    • Porcini — They look similar but the porcini has white to yellow pores and lacks the dark stalk netting.

    Science

    Family
    Boletaceae
    Genus
    Tylopilus
    Order
    Boletales
    Class
    Agaricomycetes
    Native range
    Widely distributed across the Northern Hemisphere in temperate forests.
    Conservation
    This species is common and not of conservation concern.

    It lives in a symbiotic mycorrhizal relationship with tree roots, exchanging nutrients for carbohydrates.

    Value to wildlife
    mycorrhizal partner for trees
    Uses
    ecological study, mycorrhizal research

    Through the year

    JFMAMJJASOND
    Flowering
    Fruiting
    Foliage

    Ecological indicators

    Salinity
    0/9
    Moisture
    5/9
    Soil reaction
    3/9
    Light
    0/9
    Temperature
    4/9
    Nutrients
    3/9

    Taxonomy resolved against GBIF.

    Questions people ask

    Is the bitter bolete poisonous?
    No, it is not toxic, but it is considered inedible because of its unpleasant taste.
    How do I tell it apart from a porcini?
    Look for the dark, raised network pattern on the stalk and the pinkish color of the pores as it matures.

    Where the name comes from

    The genus name Tylopilus comes from Greek for knob and cap, while the species name felleus refers to its gall like bitterness.

    Good to know

    • The bitterness is so strong that a single specimen can ruin an entire pot of soup.
    • It forms a symbiotic relationship with the roots of coniferous and deciduous trees.
    • The scientific name felleus means bitter as gall.

    Keep your bitter bolete growing

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    This guide was generated with AI and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.