Hortiboletus bubalinus

Description

Hortiboletus bubalinus is a species of bolete fungus in the family Boletaceae. The family name, Hortiboletus, refers to the Latin Hortus meaning garden where the bubalinus can often be found growing with Poplar, Populus, or Lime, Tilia. It has a pale brown with slight red or yellow hues, lighter towards the edge. Starts rounded but becomes flatter and more uneven with age. Pores are yellow to pale yellow sometimes with olivaceous hints. Stem fairly thin for a Bolete, pale background covered in vertical red fibers. The flesh is off-white/yellow in the stem. White in the cap staining pink under the cuticle and blue above the pores. Often habitat in parks, gardens, and urban environments under lime or poplar.

Originally described in 1991 as a species of Boletus, the fungus was transferred to Xerocomus in 1993. It was transferred to Hortiboletus by Bálint Dima in 2015.

Synonyms: Boletus bubalinus Oolbekk. & Duin, 1991, Xerocomus bubalinus (Oolbekk. & Duin) Redeuilh, 1993.

Mushroom Identification

1. Cap

   Up to 5 cm, at first hemispherical, later convex to flattened, ochraceous, buff with or without apricot hues, pale brown, reddish-brown, yellow-brown to coppery brown, usually paler towards the cap margin, dry, velvety, later smooth or very finely cracked.

2. Stem

   Cylindrical, ventricose or club-shaped, yellowish, and usually covered throughout with very fine red granules, often discoloring with age, blueing when bruised.

3. Tubes

   Pale yellow to yellow with olivaceous tint, blueing when injured.

4. Pores

   Are concolorous with the tubes, blueing when bruised.

5. Flesh

   Whitish in the cap, distinctly pinkish below the cap cuticle, yellowish in the stipe, orange-brown in the stipe base, sometimes with few orange-red dotes, blueing in the cap.

6. Odor and Taste

   Not distinctive.

7. Spores

   11–15 × 4.5–5 μm, smooth. Pileipellis palisadoderm of septate hyphae of cylindrical or rounded, slightly incrusted cells.

8. Spore Print

   Brown.

9. Habitat

   In urban areas, parks, lawns, mycorrhizal with poplars (Populus) or lime (Tilia). One record with a hornbeam (Carpinus) from Britain. It is suggested by the literature that the range of mycorrhizal hosts is probably wider and includes birch (Betula), beech (Fagus), and spruce (Picea).

10. Distribution

    Not yet fully understood. Recorded from Bulgaria, France, Hungary, Italy, Netherlands, Norway, Sweden, and UK.

Photo sources:

Photo 1 - Author: MichelBeeckman (CC BY-SA 3.0)

Photo 2 - Author: Lukas from London, England (CC BY-SA 2.0)