Sepia Bolete

Xerocomellus porosporus (Imler ex Watling) Šutara

1 Observations

2 weeks ago Last Observed

Xerocomellus porosporus — Malcolm Storey

The Sepia Bolete (Xerocomellus porosporus) is a smallish, dry-capped bolete. The cap is snuff-brown to olivaceous, finely velvety when young, and soon splits into a crazy-paving pattern that shows pale flesh in the cracks. Underneath are angular, pale yellow pores that darken with age and turn blue when bruised. The greyish-brown stem has a fine red zone near the top. The spores are the best clue, as many are squared off at one end.

It is an ectomycorrhizal species found in broadleaved woodland, most often under oak, with beech also recorded. Fruiting runs from summer into late autumn, with most finds in the autumn. Leon's data treats it as widespread and common, though several sources describe it as uncommon to rare, probably because it has often been confused with other species.

It is easily mistaken for other Xerocomellus species. Xerocomellus chrysenteron has reddish flesh beneath the cracked cap surface, which this species lacks. Xerocomellus pruinatus usually has a darker, plum or red-brown cap that does not crack. Xerocomellus cisalpinus has a yellow stem flushed red below, with flesh that bruises blue more readily. Pseudoboletus parasiticus grows on earthballs and has no red on the stem. It is regarded as edible but of poor quality, and the lookalikes make careful identification essential.

Spore Print

Season

Native

non-toxic

Distribution

Widespread and common

Habitat

Under Quercus

Etymology

Xerocomellus is from the Greek xeros, meaning dry, and indicates a close relationship to the genus Xerocomus, whose members have dry, velvety caps. The specific epithet porosporus combines poro-, meaning a pore or opening, with sporus, relating to spores. It refers to the germ pore at the truncated end of the spore, which is the feature that sets this species apart from its relatives.

Associates

Fagus, Quercus

Conservation

LC - Least Concern

IUCN Red Data List - Xerocomellus porosporus
Assessment date: 2026

Cap

The cap surface soon cracks, and the cracks open up to expose the pale flesh beneath, giving a crazy-paving look. It is finely velvety when young, and the cracking becomes more obvious as the cap expands.

Colour
Width	4 - 8 cm

Pores

Small and angular, pale lemon-yellow when young and darkening to a more olive-yellow with age. Mature pores slowly bruise blue when pressed or handled.

Colour
Bruising

Tubes

Yellow at first, becoming greenish olive as the fruit body ages. The tubes bruise bluish when cut or damaged, though often only slowly.

Colour

Flesh

The flesh rarely stains blue when cut, and often shows no change at all. It stays pale yellow and is pleasant and mild.

Colour
Odour	Pleasant
Taste	Mild

Stem

There is a fine red zone near the apex of the stem, which can be easy to overlook. The stem is yellower at the very top and may bruise reddish-brown when handled.

Colour
Height	9 - 10 cm
Width	20 - 30 mm
Bruising

Spores

Many of the spores are truncated, as if chopped off square at one end. This is the best feature for separating the species from its close relatives and needs a microscope to check.