ABSTRACTThe species composition of vesicular-arbuscular mycorrhizal fungi (VAM) are described from experimental plots in tallgrass prairie at Konza Prairie Research Natural Area, Manhattan, Kansas. Treatments include topography (four positions downslope) and burning frequency (annually burned and infrequently burned). Multivariate and univariate analyses indicate that gradients of variation in VAM species are related primarily to topography and burning frequency, and secondarily to original plot position within experimental rows. Spore numbers of seven of the most abundant species are directly related to topography; three of these also show an interaction with burning frequency. Although the distinction between direct and indirect effects of topography and burning frequency cannot be made with these data, a parallel response of vascular plant species frequency to the topographic gradient was observed.