Honey Fungus (Armillaria)

The largest living organism on Earth by area/Biology & Ecosystems

A single specimen of Armillaria ostoyae in Oregon's Malheur National Forest covers about 9.6 square kilometers, making it the largest known living organism on Earth by area. Estimated to be between 2,400 and 8,650 years old, this massive fungal network spreads underground through dark root-like structures called rhizomorphs. Above ground, it produces clusters of honey-colored mushrooms each autumn. Despite its size, most of its biomass is hidden beneath the soil, slowly killing trees by infecting their roots.