16 Facts About Fungi and Mushrooms That Rule the Underground

The Hidden Kingdom

1. Fungi are more closely related to animals than to plants. Despite being historically classified as plants, genetic analysis reveals that fungi and animals diverged from a common ancestor about 1.5 billion years ago, while plants branched off earlier. Like animals, fungi are heterotrophs that must consume organic matter for energy.

2. The largest living organism on Earth is not a whale or a tree — it's a fungus. A single Armillaria ostoyae honey fungus in Oregon's Malheur National Forest spans approximately 9.6 square kilometers and is estimated to be between 2,400 and 8,650 years old. It weighs an estimated 35,000 tons.

3. There are an estimated 2.2 to 3.8 million species of fungi on Earth, but scientists have only described about 150,000 of them. This means we've identified less than 7% of all fungal species — the vast majority of the fungal kingdom remains undiscovered and unstudied.

The Wood Wide Web

4. Mycorrhizal fungi form vast underground networks connecting trees and plants, dubbed the "Wood Wide Web." These fungal threads, called mycelium, can transport water, carbon, nitrogen, and other nutrients between different plant species, effectively creating a communication and resource-sharing network beneath the forest floor.

5. Through these fungal networks, older "mother trees" can detect distress signals from neighboring seedlings and send them carbon and nutrients. Research by ecologist Suzanne Simard showed that Douglas fir and paper birch trees exchange carbon through mycorrhizal networks, with the flow direction changing based on the season and each tree's needs.

6. Plants connected to fungal networks can also send chemical warning signals to each other. When a plant is attacked by aphids, it can transmit alarm signals through the fungal network, allowing neighboring plants to preemptively produce defensive chemicals before the pests reach them.

Fungi as Medicine and Food

7. Penicillin, the first antibiotic, was discovered by Alexander Fleming in 1928 from the mold Penicillium notatum. This fungal discovery revolutionized medicine and has saved an estimated 200 million lives since its introduction. Before antibiotics, a simple scratch could be fatal.

8. The yeast Saccharomyces cerevisiae, a single-celled fungus, has been humanity's companion for at least 9,000 years, enabling the production of bread, beer, and wine. It was also the first eukaryotic organism to have its entire genome sequenced, in 1996, making it a cornerstone of genetic research.

9. Truffles, among the most expensive foods in the world, are underground fungi that form symbiotic relationships with tree roots. The world's most expensive white truffle sold for $330,000 in 2007, weighing just 1.5 kilograms. Truffles cannot be cultivated reliably and must be found using trained dogs or pigs.

Bizarre and Beautiful Fungi

10. The zombie-ant fungus, Ophiocordyceps unilateralis, infects carpenter ants and manipulates their behavior. The fungus compels the ant to leave its colony, climb to a specific height, and clamp onto a leaf vein with its mandibles before dying. The fungus then sprouts a stalk from the ant's head to release spores onto the forest floor below.

11. Bioluminescent fungi exist in over 80 species worldwide. These mushrooms produce a ghostly green glow through a chemical reaction involving luciferin and luciferase — the same compounds that make fireflies glow. The glow attracts insects that help spread the fungus's spores.

12. The Devil's Tooth fungus, Hydnellum peckii, oozes blood-red droplets when young, earning it the nicknames "bleeding tooth fungus" and "strawberries and cream." Despite its alarming appearance, it is not toxic — just incredibly bitter. The red droplets contain a pigment with anticoagulant properties similar to heparin.

Fungi and the Future

13. Mycelium-based materials are being developed as sustainable alternatives to plastic, leather, and even building materials. Companies are growing mushroom-based packaging that decomposes in 30 days, mycelium leather for fashion, and even mushroom bricks that are fire-resistant and stronger than concrete.

14. Certain fungi can break down plastic and petroleum products. Pestalotiopsis microspora, discovered in the Amazon rainforest, is the first fungus found to survive solely on polyurethane and can even do so in anaerobic conditions — making it a promising candidate for landfill-based plastic degradation.

15. Fungi were among the first organisms to colonize land, appearing over 1 billion years ago. Fossil evidence of the earliest land fungi, Tortotubus, dates back 440 million years, predating the first land plants. These pioneering fungi likely helped transform barren rock into soil, enabling plant life to eventually colonize land.

16. The study of fungi, mycology, remains one of the least funded areas of biology despite fungi's critical role in ecosystems, medicine, and potential solutions to climate change. Fungi sequester massive amounts of carbon in soil through their mycelial networks, making them crucial allies in the fight against global warming.