It’s easy to look around these days and think to yourself, “Humanity is screwed”. The earth is getting hotter, the planet’s drowning in plastic, and we’re on the brink of a global energy crisis. The human population is growing faster than we can feed and accommodate it, and we’re entering an era of pandemic viruses, the most dangerous of which seems to be stupidity. Things look bleak, but before you start washing your Prozac down with hemlock, there is hope on the horizon. Because a growing body of research is revealing that a weird, ancient and freely occurring life form could help us solve many of the problems we face as a species today. And that life form is fungus. Now, when you hear the word ‘fungus’ you probably think of mouldy bread or that stuff growing on your big toe you’re too afraid to see the doctor about. But, thankfully, fungi are more diverse than that. Depending on who you speak to, there are between 2.2 and 5 million different species of fungi in the world today, and together they form an entirely separate kingdom, making them neither plant nor animal nor bacteria. And though most of us tend to think of plants and fungi as broadly similar, weirdly enough fungi are actually more closely related to us humans than they are to plants. That really does help explain some people, doesn’t it? Fungi also include microorganisms like yeasts and moulds, which are pretty much everywhere. They exist in the ocean, on land and in every natural environment. They’re on your coffee mug, they’re on the International Space Station. They’re all over you and inside you right now. You have my permission to freak out a little bit. The fungal element most people are familiar with is the mushroom, which is essentially the fruit of a fungus. We’ve identified about 20 000 species of fungi that produce mushrooms and, as we shall see later, these vary from the deadly to the delicious to the magical. But the mushroom is only the tip of the fungal iceberg. Below lies a mysterious and often unseen web of fibrous threads that weave over, in and through organic matter. This is mycelium, the vegetative part of fungus. Mycelia help serve fungi’s number one role in the natural ecosystem: eating all the dead stuff. Fungi can’t photosynthesise like plants do because they don’t contain chlorophyll. So, like humans, they need to get their nutrients from other organisms. They do this by decomposing organic compounds: animals, wood, plants, basically anything made from carbon. But, unlike humans and other beasts who eat their food and then digest it, the mycelium likes to do things the other way around, secreting enzymes into or onto whatever it’s having for dinner , to break it down into smaller biological units before absorbing the nutrients. As if decomposing the world’s organic material wasn’t enough of a responsibility, mycelium plays another extraordinary role in natural systems. Spreading throughout the soil, mycelia connect with each other and the roots of plants and trees to form complex communication and distribution networks. When a fungus colonises the roots of a plant, it sets up a win-win relationship known as a “mycorrhiza” By connecting with plant root systems, fungi receive carbohydrates, while in return the plants receive extra water and nutrients like phosphorus and nitrogen via the fungi’s mycelium. About 90% of land plants take advantage of this set up, which also helps plants build up their immune systems, making them stronger and encouraging growth. When mycelium first connects to a plant’s root system, it triggers a defensive chemical response in the plant. This process, called priming, makes plants’ immunity reactions faster and more efficient. But the mycelia impact goes far beyond single plants. We now know mycelium networks join up, connecting plants with each other in a subterranean information superhighway. Trees use the mycelium network to transfer carbon, nitrogen and phosphorus between them, helping maintain nutrient balance across many different plants. It appears older trees even help younger ones to grow – a study of seedlings growing in the shade where they are more likely to be short of nutrients revealed they received carbon from donor trees around them via mycelium. And though these discoveries are still pretty new, it seems plants can even use the mycelium net to communicate. Studies have shown that when a single plant is infected with a harmful fungus or attacked by pests, it sends out a warning via the mycelium network, with plants connected to that network showing a more potent immune resistance. Plants that aren’t connected never get the message and show weaker immune responses. By studying these stange and complex interactions, scientists believe we may be able to dramatically improve farming techniques that have traditionally destroyed these precious mycelium networks, which – along with the rise in cultivation of edible mushrooms in third world countries, could help in the fight against world hunger. But it’s not all holding hands and “love thy neighbour”. Some plants turn the mycelium internet into the dark web by using it for nefarious purposes. Some orchids, for example, have little or no ability to photosynthesise, so they hack into surrounding plants via mycelium to steal the carbon they need. Other plants are even more mercenary. When competing for resources like water and light, they use mycelium to release chemicals into the soil that harm rivals or deter them from growing. This process, called “allelopathy”, is known to happen via tree leaves and roots, but the discovery that fungi are helping to amplify the effect is new. As a reminder of why they weren’t invited to the cool parties at college, many biologists have started calling this dense communication network the “wood wide web”, and some estimate there to be three hundred miles of mycelium under every footstep you take through the forest. Nicknamed the humongous fungus, the largest living organism on the planet is proof of this. Growing in ancient woodland in Oregon is a single giant fungus estimated to be 2,400 years old. The mycelium of this armillaria ostoyae, popularly known as the honey mushroom, covers an area as big as 1,600 football fields and is more than 5 kilometres across. It extends an average of one metre into the earth, but above ground the only evidence of its existence are clumps of honey mushrooms that sporadically bloom after it’s rained. For human beings, mycelium has other uses which may be critical to getting out of the mess we’ve created for ourselves. The fantastic qualities of different fungi, especially their ability to break down carbon-based substances, promise potential miracle solutions to many of the environmental problems we’re facing. And it’s impossible to talk about these possibilities without mentioning Paul Stamets. Paul is a mushroom hunter, mushroom cultivator, and mycologist – someone who loves mushrooms so much they study them as a job. He even wears a hat made of mushrooms, and that should tell you all you need to know. Paul and his team have grown rare strains of fungi which have seemingly mystical medicinal properties while also discovering new potential for well-known mushrooms. Oyster mushrooms, for example, could help clean up oil spills. Stamets has developed a strain that is saltwater resistant and eats hydrocarbons, the organic compounds in petroleum and natural gas. One trial showed an oyster mushroom strain could reduce diesel contaminants in soil from 10,000 parts per million to just 200 parts per million in about four months. The mycelium of the whimsically-named stump fairy helmet mushroom can break down PCBs, cancer-causing chemicals once used in the manufacture of various electronic equipment. In fact, fungi could be the solution to one of the biggest environmental contaminants we have: plastic. There are estimated to be more than 150 million tonnes of plastic in our oceans, and by 2050 there might be more plastic than fish. The problem with plastic is it takes forever to break down and usually creates toxic pollution in the process. But in the last few years, scientists around the world have discovered more than 50 types of fungus that can eat plastic. The fungus pestalotiopsis microspora is capable of surviving entirely on polyurethane – the main ingredient in plastic – and can even break plastics down into new, safe fungal tissues. Mycelium isn’t just getting rid of the plastic we’ve already produced, either – it’s also being used to create alternatives to plastic packaging, which can take thousands of years to biodegrade. Beyond packaging, mycelium is a surprisingly versatile and durable material in general – the mouldy spores that grow on agricultural waste, or on old cardboard, are being converted into faux leather, textiles, furniture, and even coffins. Mycelium composites can also be made strong enough for use as a building material in the form of bricks, meaning there are implications for the construction industry too. Whether mycelium building materials could offer a solution to some of the estimated 1.6 billion people worldwide who live without adequate housing remains to be seen, but they certainly have the potential to dramatically improve the sustainability of an industry that uses over 400 million tons of building materials in the UK alone each year as well as creating an additional 100 million tons of waste. Fungi can do all of this because their cell walls are made of a molecule called chitin, which is bendy and tough. Fungi are so tough, in fact, that they help break down rock into soil. They may also be able to help reverse the soil damage caused by mass commercial agriculture, since they’re good at decomposing organic compounds and can break down some contaminants in soil, like pesticides. Pollutants may also be removed from water using mycofiltration, a process of harnessing cultivated mycelium to filter water. If cleaning up the planet and replacing high-environmental impact materials wasn’t enough, fungi may also be playing a far greater role in preventing climate change than was previously realised by helping trees absorb CO2 more quickly and slowing the process of decomposition that releases carbon from forest soils. These fung-tastic solutions to environmental problems are exciting and relatively new, but fungi have been powerful sources of medicine for thousands of years, particularly in the east. There’s the Reishi mushroom, which supports the immune system, promotes weight loss, encourages better sleep, and eases depression. Lion’s mane mushroom is excellent for the mind. It may even prevent Alzheimer’s and multiple sclerosis by stimulating the development of nerve growth factor, the stuff that helps grow new neurons in the brain. Turkey tail mushroom contains a compound called polysaccharide-K that stimulates the immune system. This compound is so effective in treating cancer it’s an approved prescription drug in Japan. Turkey tail has been linked with resistance to leukaemia cells, improving survival rates for people with certain other cancers, and improved immune systems for people receiving chemotherapy. There are many more examples of fungi medicine, but Western medical science only really cottoned on to this fairly recently. In 1928, medical physician and scientist Alexander Fleming returned from vacation to find an unusual bacteria-munching mould growing on a petri dish in his lab. This fluffy white mass would become penicillin, the world’s first commercially-produced antibiotic. Fungus is also behind the drug cyclosporine, which helps prevent rejection of transplanted organs. An ancient and near-extinct mushroom known as agarikon was first documented in 65 AD in Materia Medica, the first known manual of herbal medicine, and is possibly the longest-living mushroom on earth. It’s also the focus of intense medical study for its potential in helping us fight viruses which, as you may have noticed, have been a bit of an issue recently. Agarikon contains antiviral molecules new to science, and initial studies show impressive activity against viruses such as pox, swine flu, bird flu, and herpes. The fungus also has potent anti-inflammatory and antibacterial properties. In ancient Greece, it was recommended in the treatment of consumption – now known as tuberculosis – and it might prove to be a game-changer in the fight against multidrug-resistant TB. Beyond physical health, though, mushrooms are increasingly being shown to have mental health benefits. Of the tens of thousands of varieties in existence, just a few hundred of them are known to be psychoactive, which is science-speak for: eat one and you’ll trip your balls off. And most of these species have this effect thanks to an active ingredient called psilocybin. I am, of course, referring to the fabled magic mushroom. Rock paintings in Australia suggest eating these special fungi goes back to at least 10,000 BC, while more rock paintings, this time in Spain, show prehistoric people in present-day Europe were blowing their minds in at least 4,000 years BC. Mushroom mythology among the Mayans goes back to 1,500 BC, and. in the 16th century, a Spanish priest called Bernardino de Sahagun wrote about the use of magic mushrooms among the Aztec people. But, when the Spanish conquered much of central and south America, many religious rituals were outlawed and magic mushrooms were forced to go into cultural hiding. It wasn’t until the mid-20th century that they resurfaced in western countries. In 1939, two ethnobotanists named Schultes and Reko published a paper in Harvard University Botanical Museum leaflets detailing the use of psilocybin mushrooms by practitioners in Mexico. Just under twenty years later, two mycologists named Wasson and Heim travelled to Mexico to check the story out for themselves. They ate mushrooms under the guidance of a local shaman and then wrote about the experience in Life Magazine in 1957. An editor named the piece “Seeking the Magic Mushroom,” and psychoactive mushrooms have been ‘magic’ in popular culture ever since. The article was picked up by Timothy Leary, a Harvard psychologist and big fan of hallucinogenic drugs, who began to experiment with psilocybin. You might know his name from the 1968 Moody Blues hit Legend of a Mind – apparently advocating the use of psychedelic drugs is a good way to win brownie points with rock and roll types. Psilocybin was soon a favourite of hippies everywhere and strongly linked with the growing counterculture of the 60s and 70s. But it wasn’t all free love and psychedelic dream catchers. Around this time, psilocybin was isolated and synthesised by Albert Hofman, the same guy who invented LSD, and used in hundreds of clinical trials. Psychologists, psychiatrists and other mental health professionals saw promising results for patients with conditions like depression, anxiety, alcoholism and OCD. But the 70s saw a ban placed on the use of psilocybin for anything other than medical research. Studies ground to a halt, and nothing happened for about thirty years until research started up again in the 2000s. A research group at John Hopkins University was the first to obtain regulatory approval in the US to study psilocybin, though by then it was, in the US and many countries, a Schedule 1 substance, making it as illegal as heroin or crack .But, last year, the University launched the Johns Hopkins’s Center for Psychedelic and Consciousness Research dedicated to uncovering the medical potential of substances like psilocybin. Using better science, more sophisticated technology and improved methods, more and more academic studies are confirming the hypothesis from 50 years ago: that the active ingredient in magic mushrooms can be a powerful treatment for multiple mental health disorders. So, next time you sneer at a piece of mouldy bread, just remember fungus could help the environment, your body and your mind, and the whole of humanity d. But then throw it away anyway, because saviour of humanity or not, mouldy bread is gross.