It turned out that G. lucidum was not a monophyletic species, and further work needed to be done to clarify this taxonomic problem. They also found that G. resinaceum from Europe, and the North American G. lucidum', which Adaskaveg and Gilbertson found to be biologically compatible in vitro, did not cluster together.Adaskaveg, J. E., and Gilbertson, R. L. 1986. Cultural studies and genetics of sexuality of Ganoderma lucidum and G. tsugae in relation to the taxonomy of the G. lucidum complex.
It was found that G. lucidum does not constitute a single species, necessitating further investigation to resolve this taxonomic dilemma. Moreover, studies on G. resinaceum from Europe and North American G. lucidum revealed that they do not form a cohesive group, despite exhibiting biological compatibility in vitro.