Ten Simple Rules For Fungus Foraging

Mushroom foraging

It’s mushroom season again, which means there’s some very fine eating to be had for the cost of a morning walk in the woods and fields. But which of those many strange fungal fruiting bodies are safe to eat, and which will make you very ill indeed? There are several killers out there, and plenty more that can cause deeply unpleasant symptoms…but there are also some tasty treats and unusual delicacies which it would be a shame to miss.

So how to tell the difference? If you have the opportunity to forage with an expert, you certainly should – but there are some simple rules that will weed out the dangerous specimens. The same rules will have you discard some good eaters too, but it’s better to be safe than sorry.

Foraging & Cooking Basics

1. Carry your harvest in an open basket, if you can, or a cloth or paper bag. At a push, small tupperware boxes…but never a plastic bag, please.
2. Take a small knife, and cut every mushroom in half. As well as checking for maggots or other intruders, the flesh of some fungus changes colour when exposed to the air, which can be an identifying factor.
3. Take gloves. Some fungal toxins, and the psychotropic substances that are found in a few species, can enter the body through the skin.
4. Play safe. If you’re not entirely sure that what you’ve picked is edible, don’t eat it.
5. Cook everything you intend to eat. Cook it well – for some that means a long slow casserole, for others a shorter time but in hot oil (or bacon fat).
6. It’s worth being cautious the first time you eat a new mushroom. Try a small amount first, on the off chance of allergies and if there are no ill effects (and you like the taste), you can go looking for more, with more confidence.

Mushroom Identification Rules

1. If it’s purple, you can eat it.

This is probably the least useful rule. The Amethyst Deceiver [Laccaria amethystina] is edible…and very purple when young (it fades with age, hence the ‘deceiver’ label). It can be found ‘trooping’ (growing together in large groups) in woodland. If you find a patch of purple mushrooms on the forest floor, it’ll be Laccaria amethystina (If you find yourself asking “Is that purple?”, don’t eat them). They’re not, alas, particularly flavourful, nor do they retain their colour after cooking, but they make an acceptable addition to a rustic casserole or such.

2. If it changes colour when you cut it in half, then throw it away

A much more useful rule. Some perfectly good edible mushrooms change colour – but so do most of the dangerous species. Cut your mushrooms as soon as you pick them, and watch the inside of the stem and the flesh of the cap. Colour change (usually to blue or red) occurs within seconds – but check them again when you get home, just in case. It bears repeating, and I will: if in any doubt, don’t eat them.

3. If it has white gills, throw it away (preferably without touching it)

Again, a rule that wastes some edible mushrooms but also eliminates the worst of the few deadly species. ‘Gills’ are the segmented underside of the cap, such as you see on a supermarket standard mushroom. Some fungi lack gills (some lack caps, and many more bear no relation to a mushroom at all, but we’ll get to that…) Where you might expect gills, you’ll sometimes find a spongy surface of pores. There are some good eaters in that family, including the traditional ‘penny bun’ (commonly called ‘cep’ or ‘porcini’) [Boletus edulis]. Several of them change colour (see Rule 2), but not the penny bun, which is a highly regarded ingredient – low in fat and carbs but high in protein, vitamins, minerals and fibre.

4. If the stem has a ‘collar’ or ‘skirt’, throw the whole thing away

Look for any sign of a ring of growth around the stem, at any point from the ground up to the cap. You’ll lose some eaters, but you’ll not die – which seems like a good trade off to me.

5. Don’t eat the fairy toadstools

The distinctive red cap with white spots, the throne or home of fey creatures in art, is the fly agaric [Amanita muscaria]. It’s poisonous. It also has white gills and a white ‘collar’ on the stem – so rules 2 and 4 apply already anyway. But it’s one of the more recognisable mushrooms, which a child might easily be drawn to, so worth flagging up with its own entry. Don’t eat it.

6. If it looks like a piece of beef steak nailed to a tree, you can eat it

As with rule 1, if you have to ask “Is that what he meant when he said it looked like meat?”, don’t eat it. But if you suddenly exclaim “Why has someone nailed a steak to a tree?” and look around for the hidden camera, that’s a beefsteak fungus [Fistulina hepatica]. It even ‘bleeds’ when cut. It’s fairly common on oak and sweet chestnut, though harder to identify as it ages. Even the young specimens can be tough, so need a long slow cook. It has a slightly sour taste.

7. If it looks like expanded insulation foam leaking from the trunk of a deciduous tree, you can probably eat it

If you see a sulphur-yellow bracket fungus halfway up a tree, break some off in your hand – if it tears apart like cooked chicken and weeps a clear liquid when cut, that’ll be chicken-of-the-woods [Laetiporus sulphureus]. It deserves its name – it can be cooked like chicken, and acts a little like tofu in picking up the flavours of a dish. It can be frozen without impairing it, which can be useful – the Guinness World Record specimen, found in the New Forest in 1990, weighed over 45 kg.

8. If it’s golden, eggyolk yellow, trumpet shaped and trooping in patches under deciduous trees, you can eat it. Or sell it to the French.

Chanterelles [Cantharellus cibarius] are highly prized and readily recognised. Once again, if you’re not sure, leave them behind – but there is nothing else that looks like them. Not even the False Chanterelle, which is never as yellow as the real thing. I prefer them fried in a splash of light vegetable oil and served on hot buttered toast, but any method that doesn’t interfere with the delicate flavour will do.

9. If it looks like a golf-ball, or a tiny sheep curled up in the grass, you might be able to eat it

The puffball [various fungi within the division Basidiomycota] can be an excellent addition to a breakfast, sliced and fried in bacon fat or butter (or something less enjoyable but much healthier…). Not all puffballs are edible, by any means. If it has any sort of stalk, leave it behind. If its outer surface is not smooth, leave it behind. You’ll leave some edible specimens, but as ever, we’re playing safe. Cut these in half too – not so much to look for colour change, but to check for sporing. You may have played with a puffball as a child – older specimens ‘burst’ and release puffs of dark spores that have grown inside it. If the inside of your specimen is not uniformly smooth and white, leave it behind.

10. If you can detect it by smell, it’s a delicacy

The stinkhorn [Phallus impudicus], a phallic, foul-smelling, fly-attracting fungus, is the only mushroom that can be found by sense of smell. If you’re wandering through the woods and get a whiff of something slightly offensive – a sour, rotting, unpleasant aroma – have a root around in the undergrowth and see if you can find a stinkhorn ‘egg’. The ‘adult’ form is inedible (and unappetising), but you may be lucky enough to find a small leathery ‘egg’, which is the young form. They have two layers of ‘skin’ with a slimy jelly between them, and at the centre there’s a little curled-up stinkhorn mushroom. Wash off the jelly (one of the few mushrooms that benefits from the application of water – most should be cleaned with a brush, because they soak up water too readily). Thinly slice the central section, fry lightly and serve on crisp toast. It’s quite a challenging taste – but if you like marmite and gentleman’s relish and such, you may well enjoy it.

There are many wonderful and delicious mushrooms that will get left behind by these rules – but if you follow them rigidly, always checking for colour change and always erring on the side of caution, then you should come to no harm (unless you find yourself in a territorial dispute over the right to a patch of chanterelles…)

Steve Wallis

Steve Wallis has been foraging for fungi since 1993, with years of experience working on a wild site of woodland and heathland in the New Forest. All of the mushrooms described here, and many more besides, grew profusely across the estate, sparking an interest that became a passion.  Steve believes that good mushrooms are going to waste, because we regard them all (in the wild) with suspicion – even though we readily learn to distinguish sloe and elder, for example, from all the poisonous berries.

Steve is an active member of the local Green Party and author of Common Words an anthology about the history, landscape and wildlife of Greenham Common.



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