10 Fascinating Facts About Mushrooms

From the world's largest living organism to glowing fungi and medicinal marvels — the fungal kingdom is full of surprises. (2026 Update)

Mushrooms are just the tip of the iceberg. The visible part — the cap and stem you might spot in a field — is only the fruiting body: the reproductive structure that a fungus produces when conditions are right. Beneath it, often invisible, is a vast network of mycelium that can extend for hundreds of metres through soil and wood.

The more you learn about mushrooms and fungi, the harder it becomes to think of them as simple or unimportant. They are, in fact, among the most fascinating organisms on Earth — and they shape our world in ways that science is only beginning to fully understand.

Here are 10 facts about mushrooms that might genuinely surprise you.

1. The World's Largest Living Organism Is a Fungus

In the Blue Mountains of Oregon, USA, there lives a single organism of Armillaria ostoyae — the honey fungus — that covers approximately 2,385 acres (about 9.65 square kilometres). It has been growing for an estimated 8,000 years. Most of it is invisible, spreading through the soil as mycelium.

This organism holds the record as the largest known living organism on Earth by area. It is a sobering reminder that life does not always announce itself in visible form.

2. Fungi Are More Closely Related to Animals Than to Plants

This surprises many people, but it is true. Fungi and animals share a common ancestor — they are both opisthokonta — and are more closely related to each other than either is to plants. Fungi, like animals, are heterotrophs: they cannot make their own food through photosynthesis, so they obtain energy by breaking down organic matter. Their cell walls are made of chitin, the same material found in insect exoskeletons.

This is one reason why fungal infections are so difficult to treat: because fungi are so similar to animal cells, developing drugs that kill the fungus without harming the host is genuinely challenging.

3. Mycelium Is Essentially the Internet of the Forest

One of the most remarkable discoveries of modern mycology is the extent to which trees and plants communicate and exchange resources through fungal networks in the soil. In forests, trees of the same and different species are connected by mycelium — exchanging carbon, nutrients, and water, and even sending chemical warning signals when one tree is attacked by insects or disease.

This network — sometimes called the "wood wide web" — means that what looks like a forest of individual trees is, in many ways, a single interconnected community. The mycologist Suzanne Simard's research on mother trees and forest communication has done much to bring this understanding to public attention.

For a deeper look at mycelium in the context of mushroom cultivation, see our article on mycelium explained.

4. Some Mushrooms Glow in the Dark

Bioluminescence — the production of light by living organisms — is not exclusive to deep-sea creatures. Approximately 100 known species of fungi produce a greenish glow, a phenomenon called foxfire or fairy fire. The light is produced by a chemical reaction involving luciferin, the same type of compound that fireflies use.

The evolutionary purpose of fungal bioluminescence is still debated. One leading hypothesis is that the glow attracts insects at night, which then spread the fungus's spores. Whatever the reason, glowing fungi are genuinely one of the stranger things in the natural world.

5. A Single Mushroom Can Release Billions of Spores

A single large mushroom can release several billion spores during its reproductive period. These spores are microscopic and light enough to be carried by air currents for hundreds or thousands of kilometres. Mushroom spores have been found in the upper atmosphere, transported across oceans, and even survived in the extreme conditions of space.

This extraordinary dispersal mechanism explains how fungi manage to colonise new environments so successfully. It also explains why trying to keep mushroom spores out of a cultivation environment is so difficult — they are, quite literally, everywhere.

6. Fungi Have Been Used as Medicine for Thousands of Years

Long before pharmaceutical medicine, human cultures around the world used fungi as medicine. Reishi (Ganoderma lucidum) has been used in Chinese and Japanese medicine for at least 2,000 years. Chaga (Inonotus obliquus) was traditionally used by Siberian and northern European peoples. The Ötzi iceman — the 5,300-year-old mummy found in the Alps — was found carrying birch polypore fungus, likely used as a first-aid treatment.

Modern research is now catching up with this traditional knowledge. Studies on lion's mane, chaga, reishi, turkey tail, and other medicinal mushrooms have found genuine bioactive compounds with immunomodulatory, neuroprotective, and antioxidant properties. You can read more in our guide to medicinal mushrooms.

7. Penicillin — the First Antibiotic — Came from a Fungus

In 1928, Alexander Fleming noticed that mould growing on a petri dish was killing the bacteria around it. The mould was Penicillium notatum, and the compound it produced — penicillin — became the first antibiotic and one of the most important medical discoveries in history.

By some estimates, penicillin and the antibiotics that followed have saved hundreds of millions of lives. All of this came from fungi. It is a reminder that the most important medicines sometimes come from the most unexpected places.

8. Mushrooms Can Digest Plastic and Oil

Some fungi have the remarkable ability to break down pollutants that resist almost all other biological degradation. This property — known as mycoremediation — is an active area of research. Certain species can break down polycyclic aromatic hydrocarbons in contaminated soil, digest polyurethane plastic, and even survive in radioactive environments.

The mycologist Paul Stamets, among others, has conducted research and demonstrations showing how fungi can transform heavily polluted soil into productive land within months. This has significant implications for environmental cleanup and waste management.

9. Fungi Can Control the Minds of Insects

Ophiocordyceps fungi — sometimes called zombie fungi — infect insects, particularly ants and other arthropods, and take over their behaviour. An infected ant is compelled by the fungus to climb to a specific height above the forest floor, clamp onto a leaf or stem in a fixed position, and die there — exactly where the fungus's spores will be distributed most effectively.

The mechanisms by which the fungus achieves this — altering the insect's neuromuscular system and behaviour without destroying the brain — are still being studied. It is one of the most extraordinary examples of parasitic manipulation in nature, and it has inspired both scientific research and popular culture (most notably, the HBO series The Last of Us).

10. Psilocybin Mushrooms Grow on Every Continent Except Antarctica

Magic mushrooms — fungi containing psilocybin — are found on every continent except Antarctica. Over 180 species of psilocybin-containing mushrooms have been identified, growing in tropical, subtropical, and temperate environments. They are, in other words, an ordinary part of the planet's fungal diversity.

This global distribution, combined with the extraordinary consistency of the experiences they produce, has led many researchers and thinkers to wonder about their relationship to human evolution and culture. Terence McKenna famously proposed his "stoned ape" hypothesis — that psilocybin mushrooms played a role in the rapid expansion of human cognitive capacity. While this hypothesis remains controversial, the relationship between humans and psychedelic fungi is undeniably ancient and widespread.

You can read more about the fascinating world of magic mushrooms in our introductory guide to what magic mushrooms are, and explore the profile of Terence McKenna.