Is there an easy way to tell a poisonous wild mushroom from one that is safe to eat?

Wood ear mushrooms growing on an elder tree (Image: Archant)

In the autumn sunshine, Suffolk Wildlife Trust’s Arger Fen reserve can take your breath away - the trees illuminated to show this ancient woodland at its best.

On such a day, there is no-one more interesting to take a stroll with than Matthew Rooney, forager and fungi specialist, or mycologist if you want to use the technical term.

Matthew’s day job is a mushroom cultivator - his business called Mushroom Table is based near Colchester from where he takes his produce to farmers markets in London on a weekly basis. A recent sideline is co-hosting foraging events with Michelin trained chef Carl Shillingford whose wild food restaurant in Sudbury has received rave reviews.

More variety

“In the last ten years or so, there has a been a greater interest in foraging and wild food,” said Matthew.

“It’s partly a backlash against there being too many chemicals in food and people wanting to improve their diet. People also want to increase the variety of foods they eat.”

And with fungi, I learn, there is a huge variety.

Matthew continued: “When I started growing mushrooms about the only thing you could buy in the shops was the white button mushroom – today I’m growing about 20 species.

“But when you go into foraging, the variety expands into hundreds. There are quite a few mushrooms that you can’t cultivate on a commercial scale because many mushrooms are associated with certain trees, so you have to grow the tree before you can grow the mushroom.

“There’s also a whole range of leaves, plants, fruits and nuts – the possibilities are endless and every hedgerow is teeming with potential food.

“Foraging is about learning how things change over the seasons, and when is the best time to harvest things to get the best nutrition out of them. There is always something – even in the depths of winter. Probably the hardest time is the middle of summer – the young growth has finished but the fruits haven’t fully formed and you are stuck in the mid-zone where nothing is quite ready.”

Autumn harvest

But the bumper time is autumn - the peak season for fruits, nuts....and mushrooms.

I spend a totally engaging hour and a half walking with Matthew, as he points out different types of fungi, the edibles ones: the jelly-like wood ear, which shows itself in damp conditions and grows on elder trees; the chestnut-coloured bay bolete; and the blusher, so called because its skin bruises pink if you press your finger into the flesh.

A fine example of a blusher mushroom (Image: Archant)

Matthew tells me his favourite wild mushroom is hen of the woods, which is usually found in clusters at the bottom of oak trees. The Japanese call it maitake, which means dancing mushroom - “because people dance when they find it,” he says with a glint in his eye.

I also learn about the wonders of mycelium - a subterranean fungal root system, which connects whole woods, simultaneously feeding off and nourishing host trees, fending off harmful bacteria and helping poor soils take up minerals.

There’s also a dark side to fungi - we stop to look at the poisonous yellow stainer, so called because it turns yellow at the base when cut; and smell the stinkhorn - a phallic fungi whose stench of rotting flesh attracts flies who help to spread its spores. We also admire a lone fly agaric - the classic red mushroom with white dots that is definitely not for consumption.

A walk with a difference

I put to Matthew the question I’ve been dying to ask: does he have any fast-set rules for telling whether a wild mushroom is poisonous or not? Disappointingly, there is no easy way around the issue.

He said: “Depending on what sources you go by, in this country there are between 10 and 15,000 species of mushroom.

Of those, there are around 300 that are edible and about a similar number that are poisonous. Of the poisonous ones there are around a dozen that are deadly poisonous – so, if you make an effort to learn the deadly ones you know you aren’t going to kill yourself. You might do yourself a bit of harm – but it won’t be fatal.”

Matthew Rooney (Image: Archant)

Somewhat reassured, I ask where the best place to forage is.

“As close to your home doorstep as possible,” continued Matthew.

“You don’t want to traipse miles and miles and come back with one thing. If you can just step outside your home and find stuff it’s much better. It also makes it much easier to follow how things grow – from early spring when the first leaves appear, when they start flowering, when they go start going to seed.

“With mushrooms it’s a shorter period – maybe a week - but you can watch them from being a tiny button to being a fully mature mushroom and see all the stages of growth. You can get to know the mushroom and work out when is the best time to harvest it. It can tie you into the season - not the calendar – but the actual growing season, as that can change each year depending on how cold the winter is and how wet spring is You are following nature rather than the calendar.”

Matthew also tells me that foraging can change the way you experience a walk and the countryside in general.

“A lot of the time you are looking at the ground, which tends to slow down how fast you walk and you start seeing the finer details.

“You notice things hidden away beneath the leaves you are picking, or just behind that bush you hadn’t noticed before. It may be a rare flower, a beetle, a frog, lizard or mouse.

“Because you have stopped moving, you are still - you become more aware of noises and movements around you. It opens up a whole new aspect of the countryside that you would normally fly past and not even notice.”