Field ectomycorrhizae sampled under Boletus edulis and Cistus ladanifer have been characterized and described in detail based on standard morphological and anatomical characters. The described ectomycorrhiza has traits typical of Boletales: whitish with three differentiated plectenchymatous layers in the mantle in plan view forming ring-like structures and rhizomorphs with highly differentiated hyphae. The inflated, smooth cystidia-like clavate end cells on the surface of the rhizomorphs and their slightly twisted external hyphae are additional characterizing features. The Hartig net occupies 1 1/2 rows of cortical cells, partly reaching the endodermis. Not all hyphae have clamps. The identification of the fungal symbiont as B. edulis was confirmed by ITS rDNA sequence comparison between mycorrhizas and sporocarps. The singularity of this symbiotic association, as well as its ecological and practical implications, are discussed.