I would have never guessed the largest land organism is a fungus. But according to an article by Eleanor Imster, “The largest terrestrial organism on the planet is a fungus called Armillaria solidipes – or honey fungus. The largest honey fungus identified in North America is in Oregon. It measures 3.4 miles (5.5 kilometers) across!”
The fungi grow in networks of fibers called mycelia that work like plant’s roots. They grow above ground and below ground and individuals are able to fuse to other honey fungus connecting large fungal bodies together creating one large individual. The downside to this fungi is that it is also a parasite and can kill trees.
I’m not sure if I’ve seen these in our neck of the woods but I know I’ll keep my eyes open for them in the spring.