Humongous Fungus Challenges Scientists

The world’s biggest fungus — almost 6 square miles — is in Oregon’s Blue Mountains, challenging traditional notions about individual organisms, say U.S. Forest Service researchers. The clone of Armillaria ostoyae — the tree-killing fungus that causes Armillaria root disease — is estimated to be between 2,000 and 8,500 years old. “It’s one organism that began as a microscopic spore and then grew vegetatively, like a plant,” says Catherine Parks, a research plant pathologist. “From a broad scientific view, it challenges what we think of as an individual organism.” Researchers thought individual fungus organisms grew in distinct clusters marked by the ring-shaped patches of dead trees. No one expected to find the well-separated clusters represented one contiguous organism, Parks adds.