 Molecular phylogenetics analysis has shown, however, that specimens of "S. sibricus" collected from China and western North America, as well as "S. americanus" from eastern North America, are most likely "a single circumboreal taxon".Another lookalike species is "Suillus subaureus", which can be distinguished microscopically by slightly smaller, hyaline (translucent) spores (typically 7.5–8.5 by 3 µm), and an association with Quaking Aspen ("Populus tremuloides").