We talk about the internet like it’s the most sophisticated communication network ever invented. Billions of connected nodes, transferring information across vast distances, keeping everything alive and functioning. We’re very proud of it. We’ve had it for a few decades.
Fungi have had theirs for 500 million years.
The mycelial network, what scientists have taken to calling the wood wide web, operates underneath virtually every forest, field and lawn on the planet. As much as 90% of land plants are in a mutually beneficial relationship with it. Not interacting with it occasionally. Dependent on it. The relationship between fungi and plant roots, known as mycorrhiza, is so fundamental that without it most ecosystems would simply collapse. This isn’t a fringe theory. This is where the research has landed.
Here’s how it works. Fungal hyphae colonise the roots of plants, sometimes growing directly into the root cells, sometimes wrapping around them. Either way the plant’s surface area increases enormously, meaning it absorbs far more water and minerals than it ever could alone. In return the plant shares the glucose it produces through photosynthesis. The fungi need that glucose, they can’t photosynthesise themselves. So the plant feeds the fungi and the fungi feeds the plant. A deal that has been running without interruption for half a billion years.
But it goes further than nutrient exchange. Trees in a forest are connected to each other through these networks. A tree under stress from disease, drought or pest damage can signal through the mycelial network. Other trees respond. Nutrients get redistributed. It sounds like something from a fantasy novel. It’s happening right now, outside your window, under your feet, and has been since long before there were windows.
Merlin Sheldrake’s book Entangled Life is where I’d send anyone who wants to go deeper on this, and I’d recommend it without hesitation. He describes the mycelium as one large chemically sensitive membrane. The entire surface of a fungal network can detect and respond to chemical signals. One molecule, landing anywhere on that vast network, can trigger a behavioural change across the whole thing. I remember reading that and having to put the book down for a minute. An organism potentially covering acres of forest floor, responding as one, to a single chemical signal. We built the internet and thought we’d invented something new.
Now here’s where it gets properly interesting. Or unsettling, depending on your perspective.
The anti-cancer properties we long attributed to the yew tree have since been found to belong to the fungi living inside it. The leaf cutter ant farms fungi, feeding it cut leaves, depending on the resulting growth entirely for food. Neither the ant nor the fungi can survive without the other now, though as I’ve said before it’s genuinely unclear who’s running that relationship. And Sheldrake raises the question directly: if fungi are metabolically active inside plants, producing compounds we thought were the plant’s own, are the fungi using the plants? Are the plants puppets?
I wrote about this and the idea stuck with me. Could it be that fungi are controlling the trees and plants, using them as puppets? And if so, what does that say about us? Because we are full of fungal organisms. Spores inside us right now. Fungal compounds in our medicines, our food, our drink. At a molecular level we have more in common with fungi than we do with plants. We share biochemical innovations with them that we don’t share with the rest of the natural world.
So who exactly is running this network?
I don’t ask that to be dramatic. I ask it because I think it’s the most interesting question in biology right now and almost nobody outside of mycology is asking it. The wood wide web isn’t just a nice metaphor for how trees share nutrients. It’s a window into a level of biological intelligence and organisation that we are only just beginning to have the tools to see.
We built the internet and thought we’d invented connection.
It was already there. It’s been there the whole time.
May the spores be with you.