Think about where your food comes from. Your medicine. The bread you eat, the drink in your hand. We think we understand these things. We don’t. And nowhere is that ignorance more embarrassing than with fungi.
What we call a mushroom, that thing you slice up and throw in a pan, is not the organism. It’s the fruiting body. The bit that pokes above the ground and gets all the attention. The real organism, the thing that’s actually alive and doing all the work, is underneath. It’s called the mycelium. And once you actually understand what it is, you’ll never look at a field, a forest, or even your lawn the same way again.
Here’s the image that clicked it for me. Think of the mushroom as an apple. The apple is the fruit, the end product, the thing you see and pick. But the tree is still there whether the apple is or not. The mycelium is the tree. It can live for centuries. The mushroom comes and goes, sometimes overnight, but the mycelium just keeps growing, keeps expanding, keeps doing what it does. We see the mushroom and think that’s the whole story. It isn’t even close.
Mycelium is made up of millions of interwoven filaments called hyphae, each one just a single cell wall thick. In one teaspoon of healthy soil there are over five kilometres of mycelial strands. Five kilometres. In a teaspoon. The largest known fungal organism is in Oregon, covering 3.7 square miles. They call it the Humongous Fungus. Which is the most inadequate name anyone has ever given anything.
The lifecycle starts with a spore. Fungi fire spores into the air at forces equivalent to 20,000G. A human being blacks out at around 9G. These spores are absolutely everywhere, inside you right now, in the atmosphere, seeding clouds, contributing to rain and snow. The reach of fungi is planetary. Most of us are completely unaware of it.
Once a spore germinates, the mycelium begins to grow, consuming and digesting whatever substrate it finds. Dead wood, rotting matter, soil. It grows fast, around 1.5mm per day at the hyphal tips, and it doesn’t stop. Hit an obstacle and it splits around it, rejoins on the other side, keeps going. When conditions are right, up comes the mushroom. The fruiting body. The apple. And we pick it or photograph it or walk past it and think we’ve seen the whole thing.
We’ve seen almost nothing.
What the mycelium is actually doing down there is what really matters. It connects trees and plants, transferring nutrients and chemical signals across enormous distances. Up to 90% of land plants are thought to be in a mutually beneficial relationship with mycelial networks. Without fungi the research suggests ecosystems collapse entirely. They were the organisms that helped the first plants leave the sea. They are how soil began. Fungi fossils date back 500 million years. They were here long before us and will almost certainly be here long after.
I started growing Lion’s Mane a couple of years ago. Hericium erinaceus, a beautiful white mushroom with strange cascading tendrils, nothing like anything you’d find shrinkwrapped in a supermarket. I wanted to understand these things properly and figured the best way was to actually grow them, tend them, watch what they did. What struck me was how alive the whole process felt. The mycelium colonising the substrate, the pins forming, the mushroom appearing overnight like it had always been there, waiting. It’s not magic. It’s biology. But it’s biology that makes you feel like you’re witnessing something ancient.
Because you are.
The mushroom on your plate is the apple. The organism is something else entirely. Hidden, vast, ancient, and quietly running the show. Next time you walk across a field or through a forest, think about what’s beneath your feet. Kilometres of living filament, connecting, feeding, decomposing, regenerating. You’re walking on one of the most extraordinary organisms on the planet.
You probably just thought it was grass.
May the spores be with you.