Fungi that live in the interior of plant host tissues without causing external symptoms. The term endophyte literally means “living within” and is contrasted with epiphyte, which means “living on the surface.” These descriptive terms are used in several disciplines such as microbiology, mycology, and ecology, and at times their use is controversial. This article uses the term endophyte in a broad and topographical sense following the definition of O. Petrini (1991): “endophytes colonize asymptomatically the living, internal tissues of their hosts, even though the endophyte may after an incubation or latency period cause disease.”