Armillaria: The Giant Underground Fungi

fungi · giant organism · bioluminescence · forest

Massive underground networks. Armillaria fungi grow mostly underground as thread-like strands called mycelium, spreading through soil and tree roots across huge areas. What you see above ground is just the tiny mushroom fruiting body, like the apple on an apple tree.

Biggest living thing. The largest Armillaria specimen lives in Oregon and covers more than 3.4 square miles, making it bigger than many cities. Scientists estimate it is around 2,500 years old, so it was already ancient when the Romans were building their empire.

Some glow in the dark. Certain species of Armillaria display bioluminescence, meaning they gently glow with their own light in the dark forest. This eerie greenish glow helps attract insects that spread the fungus's spores.

Life on trees and wood. Armillaria species live on trees and woody shrubs, breaking down dead wood and returning nutrients to the soil. About 10 different species exist that were once all confused and called by the same name.