Ectomycorrhizal fungi detected on the roots of Pakaraimaea dipterocarpacea and Dicymbe jenmanii in this study.

Species-level operational taxonomic units (OTUs) are defined as sequences that are ≥97% similar across the ITS rDNA sequence region. Taxa labeled with Latin binomials or voucher numbers (TH, MCA) were identified based on ITS matches with sporocarps. Species with ECM numbers are known only from sequences obtained from ECM roots. All species are assigned to the ECM lineages defined in Tedersoo et al. [36]. The numbers shown in the columns labeled Pakaraimaea dipterocarpacea and Dicymbe jenmanii designate the number of occurrences of each fungal OTU per host species. In cases where a particular fungal OTU was detected on more than one root tip from an individual tree this was not counted as a separate occurrence. The column on the far right indicates whether or not an OTU has been found previously on ECM roots or as sporocarps at other sites in Guyana.