20-Sept London’s Fungi Treasures

Its cap can be chestnut brown with elements of orange, yellow or ochre, all moving to an olive green with age. It has yellow pores with orange-red rims. Its stem is yellow but red at its base and covered in a red net. The stem’s flesh is pale yellow yet a deep purple red at its base and on top of all this most parts turn cobalt blue when bruised or cut. Although so fascinating to look at, it unfortunately causes diarrhoea if eaten. Other boletes recorded in the London area include B. rubellus, B. vaccinus, B. radicans, B. rubinus and B. pruinatus, the last species tending to be seen at the end of the season.

Most are found under oak but others have associations with beech, birch, Scot’s pine, larch and even alder, aspen and hazel. They are not going to be found under ash, rowan, white beam, cherry, hawthorn or sycamore but are likely to be found near old veteran oaks, especially in the short grass and moss beneath them. Consequently medieval deer parks and old boundary banks in woods are especially good places to look for them. The bolete season is a long one, usually starting in late summer and finishing in November but on the whole they tend to appear in the early part of the season so now is a good time to look for them. Other good places to find them are Epping forest, Burnham beeches and Richmond park.

There are four main types. There are those with the familiar cep or penny-bun shape (Boletus spp)., scaly-stemmed boletes (Leccinum spp.), those with sticky viscous caps (Suillus spp.) and then a number of oddities all of which still have pores rather than gills.

The cep (French), porcini (Italian) or Penny bun (English) is the greatest prize of all. This is the most sought after edible fungus in the world, except perhaps for truffles, and can be found dried in most London supermarkets. In the wild it has a light brown cap, dumpy shape, white pores that age to a pale olive colour and a diagnostic white ‘net’ at the top of its stem. ‘Nets’ are interconnecting threads laid on the surface of stems, especially at the top of them.

It can be found throughout London, but being such a large species it seems only capable of producing a small number of fruiting bodies when it does occur. Londoners traditionally never tell anyone where they find them so that they can return to the same location and collect more later. Now they are likely to be firm and solid and not attacked by maggots. Later, if left, they get far larger, softer and more overblown and are quite useless to eat. As ever with fungi, there are other species that are similar-looking to ceps. These are Boletus aestivalis, B. aereus and B. pinophilus, but instead of being poisonous, in this case they are all just as good to eat. Londoners, especially eastern Europeans, like to pick the bay boletus B. badius which is often found in better numbers and also usually in better condition.

The most commonly found species in our area is loosely called B. chrysenteron which probably occurs at one time or another in almost every wood in London. It is usually small with a brown ‘cracked’ top and red stem which tends to be yellow at the top.

It is often far too small and soft to merit picking. There are several similar species including B. porosporus which is very similar but with much duller colours. A typical feature of many boletes is that they turn blue when bruised or cut. This colour change can be quite dramatic in species such as B. erythropus and B. pulverulentus. The latter species is likely to be totally blue by the time it reaches home. Blueing occurs much more slowly in species such as B. lanatus and in B. albidus a much paler blue than usual is produced. Another typical feature of the group is that many have quite fierce blood red colours making them quite sinister looking.

The most commonly noticed is B. erythropus, partly as it is often so large, has a snuff coloured cap, blood red pores and blues so intensely when cut. The only really dangerous species, especially if eaten raw, is the Satan’s boletus B. satanas and the similarly deep red B. legaliae. This small group of deep red boletes tend to cause indigestion, gastric upsets or worse and so are best avoided. If deciding to be adventurous with boletes it is also worth getting to know the bitter bolete Tylopilus felleus and the scarlet-stemmed bolete B. calopus. Both are so bitter they instantly destroy any dish they have accidentally been added to.

Few boletes are scented, but one or two may be partially recognised by their smell e.g. B. impolitus (iodine), B. fragrans (fruity) and B. satanus (rotting garlic) and B. piperatus may be identified by its taste as it is so peppery. Another group of more difficult to identify boletes are those with felty or velvety brown caps.

Two of the more common ones have especially bright yellow pores i.e. B. subtomentosus and B. lanatus. In the latter species the pores are larger and more angular. One last species that has to be sought out, although it might take a few years, is the lurid bolete B. luridus. One specimen can produce as good a range of colours as any other plant or animal in London.