Although geographically separated, the forests of eastern North America and northwestern India share a number of ecologically important ectomycorrhiza-forming tree genera in common. Prominent examples include Quercus (oak), Pinus (pine), Picea (spruce), and Abies (fir). The objectives of a research project funded by NSF grant INT-9902175 were (1) to compare the species diversity and taxonomy of selected groups of ectomycorrhizal fungi associated with upland coniferous and oak-dominated forest communities in northwestern India and the eastern United States and (2) to elucidate the biological and taxonomic relationships existing between populations of fungi that appear to represent the same taxonomic entity in these two regions. This project represented a unique opportunity for mycologists from the US and India to collaborate on a study of ectomycorrhizal fungi in two distant regions of the world presumably having similar assemblages of fungi, based on the species names in current use (i.e., as a result of European or North American names being applied to fungi collected in India). Primary research emphasis was directed towards the family Amanitaceae, and reexamination of all taxa reported from India and determined originally as European or North American taxa indicated that virtually all of these names had been misapplied. In fact, eastern North America and India were found to share almost no species of Amanita (the largest genus in the family Amanitaceae) in common. Studies of other groups of ectomycorrhizal fungi also yielded new records for India or, in some instances, species new to science. These results demonstrated that our knowledge of the assemblages of fungi associated with ectomycorrhiza-forming trees in the forests of northwestern India is incomplete and that additional studies are needed.