The subtitle for this mighty, academic tome is How Fungi Make our Worlds, Change our Minds and Shape our Futures, which is quite a statement in itself. My knowledge of fungi is limited to food and the various mushrooms one chooses at the market. I knew nothing, or very little, of ‘another world’ under our feet, and in the air we breathe. According to Sheldrake, fungi are ‘eating rock, making soil, digesting pollutants, nourishing and killing plants, surviving in space, infusing visions, producing food, making medicines, manipulating animal behaviour and influencing the composition of the Earth’s atmosphere.’ All that, and yet fungi is largely hidden from view and more than 90% of their species remain undocumented. ‘The more we learn about fungi,’ says Sheldrake, ‘the less makes sense without them.’ Mushrooms, we are told, are only the fruiting bodies of fungi, and the place where spores are produced, before they get dispersed. Fungi produce around fifty megatonnes of spores each year, making them the largest source of living particles in the air. Yeasts that causes bread to rise or ferment sugar into alcohol, is a fungi, comprising single cells that multiply by budding into two, whereas most fungi form networks of multiple cells known as hyphae, which are ‘fine tubular structures that branch, fuse and tangle into the anarchic filigree of mycelium.’ Amongst the largest organisms on earth are the sprawling networks of honey fungi, or Armillaria, the biggest yet discovered weighs hundreds of tonnes, spreads over 10 square kilometres in Oregon and is anything up to 8,000 years old.
The author humanises his story by involving the reader in his own research in the field and taking them on his trips, like on a truffle hunt in the hills around Bologna. Truffles are the underground fruiting bodies of several types of mycorrhizal fungi, and because they are subterranean, their spores stand no chance of being dispersed by air. They came up with a novel idea, namely smell. If they could produce a pungent scent, powerful enough to penetrate the layers of soil and attract an animal that will dig it up, eat it and transport the spores to a new site, to be deposited as faeces. Job done. There is also skullduggery above ground with truffle poachers, kidnapping of prize truffle hounds worth thousands of euros and poisoned meat strewn around to kill the dogs of rival hunters. Truffles are not the only fungi that attract animals. In North America, bears go to great lengths in upending logs and clearing ditches looking for the prized matsutake mushrooms. It was reported in September that there is a shortage in Japan for this delicacy due to the under-management of the red pine forests, where they used to grow in abundance, and also an increase in nematode worms, an unwelcome American export. They are happily also food for fungi, and they display an array of gruesome methods at their disposal, including one deployed by the cultivated oyster mushroom, Pleurotus ostreatus, in which a single toxic droplet paralyses the nematode, giving the hypha enough time to grow through their mouth and digest the worm from the inside.
Lichens, a fungi visible to us, encrust as much as as 8% of the planet’s surface, an area larger than covered by tropical rainforests, and they have the ability to survive virtually anything that the Earth can throw at them. Extreme temperatures, arid deserts, the ability to lie dormant and rehydrate themselves, and the fact that they are completely full of bacteria, make lichens one of the most durable and tenacious organisms on our planet, and even in space, known as ‘polyextremophiles.’ Another trip Sheldrake takes us on is one involving LSD, taken as a clinical trial for research purposes, which sounds a little fanciful. So-called ‘magic mushrooms’, are a polyphyletic, informal group of fungi that contain psilocybin and psilocin., which are the same chemical compounds as the manufactured acid. LSD, like psiloybin, the active ingredient in many species of ‘magic mushrooms’, is classified as a pyscheldelic, (or ‘mind-manifesting’) and an entheogen (a substance that can elicit an experience of ‘the divine within’). Most trips are conducted voluntarily, but consider the poor carpenter ant whose lives are chillingly controlled by a certain type of fungus, known as ‘zombie fungi’, Ophiocordyceps unilateralis. ‘Once infected by the fungus, ants are stripped of their fear of heights, leave the relative safety of their nests and climb up the nearest plant. In due course the fungus forces the ant to clamp its jaws around the plant in a death grip. Mycelium grows from the ant’s feet and stitches them to the plant. The fungus then digests the ant’s body and sprouts a stalk out of its head, from which spores shower down on ants passing below.’
Plants make up 80% of the mass of all life on Earth and are the base of the food chains that support nearly all terrestrial organisms, and 90% of all plant species depend on mycorrhizal fungi in a mutually beneficial relationship. Algea and fungi have been partners for millions of years, and seaweeds, also algea, depend on fungi to nourish them and prevent them from drying out when washed up on shorelines. Probably the most revelatory fact to emerge from this book is the symbiotic relationship between plants and fungi, in which there are trade-offs between plant roots being able to supply carbon to fungi in exchange for minerals, like phosphorous, to the plants. Mycorrhizal research is still in its infancy, but, even more remarkable is a concept called by Radical Mycologists the Wood Wide Web, whereby whole forests communicate through a network of fungi, unseen to us on the ground. There’s more. ‘Today, the wood of some three trillion trees, more than 15 billion of which are cut down every year, accounts for about 60 per cent of the total mass of every living organism on Earth, some 300 giggatonnes of carbon.’ This book is filled with startling facts, like 75 per cent of the global production of mushrooms, almost 40 million tonnes, occurs in China. I shall never look at a humble mushroom in the same way again.