Certain fungi and plants form symbiotic relationships in which the fungus helps the plant absorb more water and soil nutrients, and the plant gives the fungus nourishment through photosynthesis--a process that fungi are unable to perform. Often the fungus attaches itself to the plant's root, as depicted in this photo.

"Some of these relationships are so absolutely important that if you took away the fungus, the plant would die," Stephenson says. "The group that relies on fungi the most are orchids. Most people know what orchids are, they recognize the beautiful flowers, but it never would occur to them that orchids could not exist without fungi."