Levels of fungal colonization in the roots of fourwing saitbush Atriplex canescens and other domⁱnant native grass and shrub species from an arid ecosystem have been studied. It was shown that colonization by septate fungal colonization was 2.7 times greater fourwing saltbush than colonization by VAM fungi. Historically studies have focused on the role of VAN fungi and how they affect the plant. The septate fungi hear several asimilarities to other types of mycorrhizae. They formed extensive non-dest ve interfaces, primarily by vegetative hyphae, within the root cortex. They enhance nutrient uptake at low concentrations and restrict uptake at high concentrations. They also protect against high salt concentrations. Some are competent decomposers and appear to enhance seedling vigor and establishment by supplying nutrients from external organic matter. They modify soil by binding sand particles to the root surface. We propose that septate fungal endophytes have a major function in ecosystem, processes.