Boletus edulis

Names

Scientific name: Boletus edulis

English name: Penny Bun; Cep

Description

This fruit body doesn't have gills beneath the cap. Instead, you will find a sponge like structure on the underside that, if you break it open, you will see is composed of lots of hollow tubes, all open at the bottom. The spores are actually being produced on cells inside those tubes and gravity will pull them down the tubes and out into the air currents as they mature.

The cap is usually a rich dark brown with a paler edge, rather smooth (although older material can become wrinkled) and greasy in damp conditions (think top of an old fashioned currant bun - that is the origin of its English name). The cap colours can vary however, occasionally being almost white. When young, the tubes beneath the fruit body will be whitish or pale buff but they rapidly turn yellow to olive with age. No part of this species should significantly change colour when bruised or otherwise damaged.

The stem is inclined to be large and swollen. Indeed the whole fruit body can grow to at least 30 cm high and around 20cm across the cap. A fruit body of that size however, is likely to be well colonised with fungus gnat larvae and should not be collected for the pot. The stem itself has a pale brown background colour and the top half is covered with a network of raised white lines that are particularly visible at the very top of the stem (use a hand lens to be sure).

This species is mycorrhizal and is thus always associated with trees, both deciduous and coniferous. It is commonly distributed through out the British Isles and often fruits quite early in the autumn. It is much sought after as an edible species.