This research was conducted to determine the nature and incidence of fungal root endophytes on fourwing saltbush, Atriplex canescens (Pursh) Nutt. Root cortex cells of fourwing saltbush in arid rangelands of the southwestern United States were analyzed and found to be regularly colonized with three types of endophytic fungi: septate, vesicular-arbuscular mycorrhizae (VAM), and Chytridiomycetes. Septate fungi were 2.7 times more prevalent than VAM and formed intimate non-pathogenic associations characterized by inter- and intracellular hyphae, coils, microsclerotia, and occasional labyrinthine or "Hartig net" structures similar to those affiliated with ectendomy-corrhizae. External hyphae formed intimate associations with soil and sand panicles. Typically, VAM were characterized by hyphae, vesicles, and (at times) coils. VAM were 2.2 times more prevalent than chytrids. Chytrids were rather common and were expressed as resting and active sporangia found within root cortex cells. The widespread occurrence of these non-destructive fungal associations with plants implies that they have an important role in plant survival in arid environments.