New Cortinariaceae species associated with , and in Guyana.

Species of the ectomycorrhizal (ECM) family Cortinariaceae (Agaricales, Agaricomycetes, Basidiomycota) have long been considered impoverished or absent from lowland tropical rainforests. Several decades of collecting in forests dominated by ECM trees in South America's Guiana Shield is countering this view, with discovery of numerous Cortinariaceae species. To date, ~12 morphospecies of this family have been found in the central Pakaraima Mountains of Guyana. Here, we describe three of these as new species of and two as new species of from forests dominated by the ECM tree genera (Fabaceae subfam. Detarioideae), (Fabaceae subfam. Papilionoideae), and (Cistaceae). Macromorphological, micromorphological, habitat, and DNA sequence data are provided for each new species.