Oregon’s Underground Giant: a single honey fungus spanning the Malheur forest
An ancient Armillaria ostoyae honey fungus in Oregon’s Malheur National Forest spreads underground across about 10 square kilometres, a single genetic individual (Genet D) identified through DNA studies and estimated to be thousands of years old; surface signs are dying trees and autumn mushrooms, while the fungus propagates root-to-root via rhizomorphs. Its claim to be the largest organism on Earth depends on measurement method—by area it may not top the list, with contenders like Shark Bay’s seagrass and Utah’s Pando by mass—yet it remains one of the planet’s most expansive single living entities.