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 discovered that G. lucidum is not a single, unified species, and more research is needed to resolve this taxonomic issue. Additionally, studies found that European G. resinaceum and North American G. lucidum do not form a cohesive group, despite being biologically compatible in laboratory tests.