LAUSR

Abstract Nothing is sterile. Insects, plants, and fungi, highly speciose groups of organisms, conceal a vast fungal biodiversity. An approximation of the total number of fungal species on Earth remains an elusive goal, but estimates should include fungal species hidden in associations with other organisms. Some specific roles have been discovered for the fungi hidden within other life forms, including contributions to nutrition, detoxification of foodstuffs, and production of volatile organic compounds. Fungi rely on associates for dispersal to fresh habitats and, under some conditions, provide them with competitive advantages. New methods are available to discover microscopic fungi that previously have been overlooked. In fungal conservation efforts, it is essential not only to discover hidden fungi but also to determine if they are rare or actually endangered.