Research interest in endophytic fungi has increased substantially, yet is the current research paradigm capable of addressing fundamental taxonomic questions? More than half of the ca. 30,000 endophyte sequences accessioned into GenBank are unidentified to the family rank and this disparity grows every year. The problems with identifying endophytes are a lack of taxonomically informative morphological characters in vitro and a paucity of relevant DNA reference sequences. A study involving ca. 2,600 Picea endophyte cultures from the Acadian Forest Region in Eastern Canada sought to address these taxonomic issues with a combined approach involving molecular methods, classical taxonomy, and field work. It was hypothesized that foliar endophytes have complex life histories involving saprotrophic reproductive stages associated with the host foliage, alternative host substrates, or alternate hosts. Based on inferences from phylogenetic data, new field collections or herbarium specimens were sought to connect unidentifiable endophytes with identifiable material. Approximately 40 endophytes were connected with identifiable material, which resulted in the description of four novel genera and 21 novel species and substantial progress in endophyte taxonomy. Endophytes were connected with saprotrophs and exhibited reproductive stages on non-foliar tissues or different hosts. These results provide support for the foraging ascomycete hypothesis, postulating that for some fungi endophytism is a secondary life history strategy that facilitates persistence and dispersal in the absence of a primary host. This thesis provides an alternate approach to identifying endophytes by considering the whole fungus interacting within its natural habitat.