Fungi are odd lifeforms, indistinguishable from plants for most people. Indeed, certain types are edible and even enhance some of our favorite foods – Roquefort, anyone? However, like plants and animals, fungi form their own kingdom of an estimated five million lifeforms (though under 200,000 are identified).  

When we hear the word fungi, mushrooms often leap to mind. But those are just a single example (like yeast and mold), and most fungi remain invisible subterranean denizens of the forest. Most of them are decomposers, leeching nutrients from other lifeforms for food. But some have unique properties that react chemically with other lifeforms, changing their behavior. Scientists are just starting to understand how vital fungi are for Earth's ecosystem.