Ben Vickers: What are some of the formative experiences that brought you to fungi? How did they come to shape your world?

Merlin Sheldrake: I became very curious as a child about how things change, and especially how things disappear. How does a solid lump of wood become soil, for example? I used to lie in leaf piles in my garden and as they decomposed over weeks I had the puzzling feeling that they were sinking into the ground. My father told me about decomposition, explaining that there are organisms that compose and organisms that decompose, and although most organisms do both, some are particularly talented decomposers. I became very curious about these organisms. If fungi and other microbes didn’t decompose the bodies of animals and plants they would pile up kilometres deep, which means that we live and breathe in the space that decomposition leaves behind. We know these organisms by what they do, but much of the time what they’ve done is represented by the space they leave behind, which makes it easy not to notice and to take them for granted.

Later, my interest in symbiosis led me back to fungi. I became increasingly curious about how organisms are able to find ways to live together and continually invent new ways to co-exist. Fungi play major roles in some of the most blockbuster symbioses on the planet, and it’s hard to talk about symbiosis for too long without running into fungi and their astonishing relationship-building abilities.

BV What about your teachers, human or otherwise, that shaped your understanding of mycelium and fungi? Were they fungi themselves or particular individuals?

MS The fungi themselves are big teachers, of course. To observe and pay attention is one of the best ways to learn, and I find it feeds the curiosity that then motivates my inquiries. The mycologist Paul Stamets was a big inspiration. I’ve known him since I was a teenager, and every time we met he would regale me with electrifying newsflashes about some astonishing new thing he had found fungi could do, or about some way he had found to solve a pressing global problem using fungi. When you spend time around Paul, you get the feeling that fungi are some of the most important organisms in the world!

The ethnobotanist Terence McKenna was another. He was a good friend of my parents so I saw a fair amount of him as a child, and he frequently talked about his fascination with fungi – psychedelic species in particular. He spent a lot of time growing mushrooms and speculating about their importance in the evolution of humanity. Terence had a talent for thinking across species and subject boundaries – quite a fungal way of exploring ideas, in fact – and would playfully reimagine the ways we talk about our relationships to different organisms and how they might relate to one another.

There are many others whose work I have found inspiring and very helpful in my fungal enquiries, particularly those concerned with thinking more broadly about the relationships between the traditional categories of “human” and “non-human”, and between “culture” and “nature”. Fungi form living bridges between organisms and can help us to find pathways between categories that we might have once thought were separate. I’ve found the work of the anthropologist Natasha Myers exciting. Among other things, Natasha thinks about the way we use our bodies to make sense of the world. For example, Charles Darwin wrote about orchids in ways that suggested that he contorted his body into shapes to try and imitate them, somehow letting a bit of the plant rub off on him. She wrote a great book about the ways that molecular biologists use their bodies to express and represent the way that proteins fold. Donna Haraway has been very helpful as well, along with the anthropologists Eduardo Viveiros de Castro and Philippe Descola, among many others.

BV One of the things that struck me in Entangled Life is the way you describe how often people when they think about fungi associate them immediately with mushrooms, which are the fruiting body of mycelial networks. You also write about yeast, and explain that fungi are literally in the air we breathe, that this form of life is everywhere around us. Could you say a bit about the vastness of the mycelial kingdom?

MS There’s such diversity within the fungal kingdom in part because it’s so huge. Our best estimates are about 2.2 – 3.8 million species, only around 6% of which we’ve described, leaving over 90% of fungal species in the category of “unknown”. So, there are lots of ways to be a fungus. When we think of fungi, we usually think of mushrooms, as you said, but mushrooms are just the place where spores are produced. And only a small number of fungi produce mushrooms; most produce spores without producing mushrooms at all. The majority of fungi live most of their lives as mycelial networks, which is how they feed. “Mycelium” is a generic term, a bit like “tree”, it describes a habit of growth – branching, fusing networks of tubular cells. Mycelium allows fungi to insinuate themselves within their food, which they then digest. Animals put food into their bodies, but fungi put their bodies into food, and mycelium is perhaps the most efficient way to do so.

But not all fungi are mycelial; yeasts are single-cell organisms that don’t form big, ramifying networks. Yeasts are also some of the most important organisms in human culture – think of bread and alcohol, both of which are made possible by yeast. Today, large areas of biotechnology revolve around yeast, and a lot of what we know about cell biology has arisen from the study of yeast as a model organism.

Most fungi live their lives as dynamic networks known as mycelium. This image shows the mycelium of a wood-rotting fungus exploring and consuming a log.

BV In terms of the language we use to describe fungi, one of the points you make in the book deals with metaphors, and how their use directly informs our thinking. In biology, for example, the dominant mode of understanding is through the metaphor of trees, their shapes and growth. The mycelial networks you discuss are more decentralised than trees, and operate in entanglements. I wondered, both on a linguistic and scientific level, whether you’ve witnessed transformations in the metaphors we use?

MS It’s a huge topic, isn’t it? Metaphors are unavoidable, and I’ve tried to bring the discussion of our metaphors into the foreground to try and think more imaginatively about some of the analogies we use, and how and why we choose some kinds of imagery over others. Trees are a really good example. I don’t want to be rude about trees – I love trees, and, like fungi, they are very decentralised organisms. But when we draw conceptual trees normally what happens is that the branches bifurcate, and then they bifurcate again, and we end up with a long sequence of bifurcation – branches diverge and diverge and diverge, but they don’t converge. On the other hand, fungal cells in a mycelial network branch but they also regularly fuse with each other (trees can do this too, but it’s not such an everyday occurrence and tends not to show up in our schematic representation). It strikes me that there are more degrees of freedom in mycelial metaphors than in tree metaphors.

BV On a different, parallel track, within the field of interspecies communication, there’s been a strong focus on mammals and mammal communication, but right now there are new significant breakthroughs happening in our understanding thanks to ecologists, such as Monica Gagliano, who are working on plant communication. You have your own ideas about this, in particular your playful notion of the “Wood Wide Web”. I’d love to hear your thoughts on the potential of interspecies communication, and whether that’s even the right term for talking about these subjects.

MS I think communication is the right term. Some people have a problem with it, but I am very happy to let this word spill over into the world of creatures without brains: I think it can be very helpful for us to use this word in different contexts to better understand what we mean by communication in the first place.

Some fungi infect insects and puppet their behaviour, overriding their instincts and forcing them to climb up high. The fungus then grows through the insect’s body and a fruiting body sprouts out of the insect from which spores rain down on unfortunate insects passing below. This image shows a carpenter ant infected with Ophiocordyceps lloydii. Two fungal fruiting bodies sprout from the body of the ant. Sample collected in the Brazilian Amazon.

There are so many different levels on which organisms communicate. Sometimes this can go on for thousands of years and lead to elaborate co-evolutionary relationships. Orchid bees are a good example. Some orchids are pollinated by orchid bees and the orchid flowers have evolved to look like sexually receptive female bees. The male bees see this floral mimicry of a female bee and they copulate with the flower. In doing so, they get covered with pollen, and when they copulate with the next flower they inadvertently pollinate it. There is a species of orchid bee that we know once existed but that is now extinct – all we know of this bee is the orchid that mimics it, which still survives, a floral portrait of an extinct animal. These different lineages of plant and animal have become entangled through the way that they signal, sense, and respond to one another.

Truffles are another example – pungent fruiting bodies of certain types of fungi that live below the ground and whose lives depend on the amazing smells they produce. For a truffle to spread its spores, it must make itself attractive to animals. The animal – pig, dog, shrew, squirrel, or whoever – digs up and eats the truffles and then deposits the fungal spores in their faeces. I think of truffles as evolutionary portraits-in-scent of animal fascinations.

Of course, elaborate networks of communication are taking place in our own bodies all the time on many different levels. Not just between your own cells, but between your own cells and the billions of microbes that live in and on our bodies – our microbiomes – without which we would not grow and behave as we do. The bacteria that live in our guts maintain steady channels of communication with our immune systems and appear to be able to regulate our behaviour by interfacing with our nervous systems – the so-called microbiome-gut-brain axis. It’s birthed a new field of study: neuromicrobiology.

BV It has become evident that we are witnessing a surge of activity in the way we approach the ecological, where experiments and new forms of understanding are rapidly expanding. Why do you think that is?

MS There’s a general ecological turn, and I think part of that is driven by the terrible crises that we continue to cause. There is a pressing need to reimagine our relationship to the organisms and ecosystems that sustain us.

BV Within that lens, are there particular moments that you believe are of particular historical importance for how fungi are seen to shape the world? And do you think that perhaps we’re witnessing a similar form of renewal and moments now?

MS It’s a fascinating question. I think it’s very important to tell histories of the world that include both human and non-human actors. There’s a classic work by historian and political theorist Timothy Mitchell called, “Can the Mosquito Speak?”, where he writes the mosquito – a vector of malaria – into a history of colonial Egypt. He argues that we cannot deal with this historical story unless we think of the mosquito as an actor. We may not be able to think of mosquitos as actors in the same sense that we think of human actors, with intentions, politics, emotions, and all the rest. Nonetheless, mosquitos have their own life cycles, habits, and needs, all of which transformed the human geopolitical world.

The story of psilocybin mushrooms in the twentieth century is another example of an organism influencing human society on a large scale. The ethnobotanist Richard Evans Schultes went to Mexico in the 1930s to investigate the teonanácatl, a sacred visionary mushroom reported in pre-Columbian codices. In Mexico, he met Mazatec people who showed him the mushrooms. He then wrote about them in a paper that ended up in a dusty archive in the Harvard Botanical Library. The poet and scholar Robert Graves found the paper, sent it to the mycologist and the vice president for public relations of J.P. Morgan bank, Gordon Wasson. Wasson became fascinated, went to Mexico, met Mazatec users of the mushrooms including María Sabina, and published his account in Life magazine. Millions of people saw this article – it was one of the first moments that psychedelics entered the mainstream press. From that point on, psilocybin mushrooms became gateway organisms to the psychedelic counterculture. Timothy Leary travelled to Mexico, had a powerful psychedelic mushroom experience, and went back to Harvard and started the Harvard Psilocybin Project – the beginning of Leary’s well-known journey with psychedelics. In the years that followed, people worked hard to cultivate these mushrooms. Today, a handful of tropical mushroom species grow in large warehouses, on people’s windowsills, in their cupboards, under their beds. A new story of domestication is in full swing and although these fungi don’t act in the way that humans do, their lifecycles, habits, needs, and chemical dispositions are a key part of the story.

BV In the context of today, it’s rather a curious coincidence that your book is being published at this time during the global pandemic. If you ever questioned whether non-human organisms had the potential to turn the human world upside down, it’s a non-starter now. You’ve been studying the microbial for a long time, and I wondered, what you’ve learnt that’s informed or affected your perspective on what’s happening now?

MS Microbes have historically been thought of as germs, as agents of disease. We would now recognise this view as dangerously narrow. Some microbes cause disease, but most don’t, and many of our health problems come from an imbalance of the microbes already living inside us. You can have a bacterium in your gut that plays a key role in your digestion but which causes a life-threatening sepsis when it gets into your blood. Is this bacterium good or bad? This is a common theme in the microbial sciences. Our limited human categories don’t always apply, whether we’re talking about the inside of our bodies or the ecology of an entire bioregion. It’s interesting with the coronavirus story: its effects vary hugely depending on the condition of people’s health, which in turn depends on many other factors. Because context seems so important, we’re forced to take a broader, more ecological perspective: what makes some people and demographics more vulnerable than others? How have governments and decision-makers amplified or reduced these disparities over the last few decades? How should we distribute responsibility and resources?

We seem set on creating the conditions for new pathogens to evolve or jump across into humans. If we deliberately invested billions of dollars into creating new pandemics we would have a hard time doing better than we’re doing now – whether demolishing rainforests and forcing wild animals and their viruses into close contact with people, or dosing millions of animals with huge quantities of antibiotics. If I think about the things that we are doing to make pandemics more likely, it is easier to think about the things we can do to make pandemics less likely. I don’t have much hope that those in power will make the right decisions, but realising that human activity is driving the evolution of new superbugs helps to frame the problem.

Having finished Entangled Life, Merlin Sheldrake decided to feed it to a Pleurotus fungus and eat the oyster mushrooms that sprouted – to eat his words. The mushrooms were delicious. He couldn’t taste any off notes, which suggested that the fungus had fully metabolised the text.

BV Fungi have been a part of your life seemingly forever. We already talked about the phenomenon associated with publications like Dennis and Terence McKenna’s P silocybin: Magic Mushroom Grower’s Guide: A Handbook for Enthusiasts (1976), which had an enormous impact in terms of people’s relationship with mushrooms. So, my question is: What is the “grower’s guide” of today? What do you think is a good entry point for people who want to have a closer relationship with fungi now?

MS There are a number of routes to take. I think growing mushrooms is a really good way in, and the easiest way to start is to get a mushroom grow kit. There lots of companies selling mushroom grow kits and they make it very easy. You spray the kit with water and flushes of delicious mushrooms start to sprout before your eyes in a matter of days. It’s fascinating to watch – they grow so fast – and it is a good jumping off point for more advanced cultivation.

Of course, you can go out walking and pay attention to which mushrooms and lichens are growing around you. Or buy ready-grown mushrooms to cook. Thinking about fungi makes the world look different – whenever you handle plants, you’re touching the outcome of a fungal relationship. Whenever you cultivate a plant, whenever you put your hands in the soil, you’re handling fungi. It’s hard to avoid them, and hard to avoid thinking about them once you start.

BV To close, I wanted to ask you, is there a par- ticular fungus that you have a special kinship with, that you feel particularly close to?

MS There was a fungus I studied a lot in Panama – a mycorrhizal fungus that forms symbiotic relationships with plants and doesn’t produce mushrooms. This meant that I couldn’t just go out and find and pick it – my contact with it was always mediated by microscopes or other scientific instruments. But the more I studied it, the more I realised that it was a symbiotic partner to most of the plants in the forest. I started to see the visible forest as an expression of the activity of this fungus, among many other microbes, and developed quite a feeling of connection with it because it helped make possible so much of the life around me.

MERLIN SHELDRAKE is a biologist and author of Entangled Life: How Fungi Make Our Worlds, Change Our Minds, and Shape Our Futures, published in May 2020 by Random House (US) and The Bodley Head (UK).

BEN VICKERS is chief technology officer of the Serpentine Galleries, London, and co-director of the publishing house Ignota.