The Ascot Hat (Hortiboletus bubalinus) is a medium-sized bolete with a smooth to finely velvety cap in reddish-brown, clay-pink, red or apricot shades, often cracking with age. The pores are lemon-yellow to yellowish-green and bruise blue, and the yellow stem is flushed with red below.
It grows on soil in parks, gardens and similar places, usually near poplar and lime but also birch, pine and oak, from Jun to Oct. It is common in southern Britain. It was first recorded in Britain near Ascot, which gave rise to its English name, and it is easily overlooked on grassy verges.
It can be confused with other small red-capped boletes such as Hortiboletus rubellus, and with Rheubarbariboletus species, which give a green rather than dark grey reaction with iron salts. The Ascot Hat is regarded as edible but of little culinary value. Never eat any bolete unless you are certain of its identification.
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Distribution
Common in southern Britain
Habitat
On soil in parks and gardens, with poplar, lime, birch, pine and oak.
Etymology
Hortiboletus comes from the Latin hortus, meaning garden, and boletus, a mushroom, referring to the gardens and parks where members of the genus are often found. The specific epithet bubalinus is Latin, meaning buffalo-like or buff-coloured, and probably alludes to the pale, buff-toned cap.
Associates
Betula, Pinus, Populus, Quercus, Tilia
Cap
Convex at first, becoming flatter with age. The surface is dry and finely velvety or powdery, often cracking in older caps to show paler flesh in the cracks. Colours range from reddish-brown to clay-pink, red or apricot, and are often paler towards the margin.
| Colour | |
|---|---|
| Shape | convex, plane |
| Surface | smooth, pruinose, cracking, velutinous |
| Width | 4 - 7 cm |
Pores
Lemon-yellow, becoming yellowish-green with age, and bruising blue when touched. The pores are fairly large and angular.
| Colour | |
|---|---|
| Bruising |
Tubes
Lemon-yellow, and bruising blue when cut or damaged. The tubes are fairly short and attached to the stem.
| Colour |
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Flesh
Pale yellow. In the cap the flesh flushes pink just below the cuticle, and there is a narrow blue zone above the tubes and in the upper stem when cut. There may be red spots at the base of the stem.
| Colour | |
|---|---|
| Odour | Pleasant |
| Taste | Mild |
Stem
The stem is cylindrical, yellow at the apex and flushed with red below.
| Colour | |
|---|---|
| Shape | cylindric |
Macrochemicals
Iron sulphate (FeSO4) turns the stem flesh dark grey. The similar Rheubarbariboletus species turn green with this reagent.
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Spores
Spore print olive-brown. Spores are smooth and spindle-shaped.
| Colour | |
|---|---|
| Shape | subfusiform |
| Ornamentation | smooth |
| Size | 10-14.2 x 4.3-5.2 μm |
Classification
- ↳ Phylum: Basidiomycota
- ↳ Subphylum: Agaricomycotina
- ↳ Class: Agaricomycetes
- ↳ Subclass: Agaricomycetidae
- ↳ Order: Boletales
- ↳ Family: Boletaceae
- ↳ Genus: Hortiboletus
Synonyms
- Boletus bubalinus Oolbekk. & Duin
- Xerocomellus bubalinus (Oolbekk. & Duin) Mikšík
- Xerocomellus bubalinus (Oolbekk. & Duin) ined.
- Xerocomus bubalinus (Oolbekk. & Duin) Redeuilh
Reference Sources
G. Kibby (2020) Mushrooms and Toadstools of Britain & Europe Vol. 1. Geoffrey Kibby.
G. Kibby (2017) British Boletes with keys to species. Geoffrey Kibby.
T. Læssøe, J. H. Peterson (2019) Fungi of Temperate Europe Vol. 1. Princeton University Press.
