ABSTRACTStructural characteristics of ectomycorrhizae formed onLarix laricinaare presented forFuscoboletinus aeruginascens, F. glandulosus, F. ochraceoroseus, F. paluster, F. spectabilis, Suillus cavipes, andS. grevillei.Ectomycorrhizal characterization permits the division of the bolete species studied into two major groups, distinguished by their extramatrical phase, as well as the form, texture, and type of tissue of the fungal components of the ectomycorrhizae. This division, based on the ectomycorrhizal structures, disagrees somewhat with the usual taxonomic classification ofFuscoboletinusandSuillusspp. The study reveals the importance of the extramatrical phase in ectomycorrhizal characterization. Study results confirm that some ectomycorrhizal fungi can be clearly identified by means of ectomycorrhizal structures.