The mushroom is the “fruiting body” of a subterranean network of microscopic hyphae, improbably long rootlike cells that thread themselves through the soil like neurons. Bunched like cables, the hyphae form webs of (still microscopic) mycelium. Mycologists can’t dig up a mushroom like a plant to study its structure because its mycelia are too tiny and delicate to tease from the soil without disintegrating.
