Drimys and Tasmannia are not a monophyletic group

Even though RHS 2004 shows Tasmannia as Drimys, recent phylogentic analysis has shown that these two groups are not monophyletic. An analysis of floral development of these two genera shows the difference in prolonged calyx tube growth forming into the calyptra as a likely parallel evolution event. Therefore, these two genera should be treated as different lineages.

American Journal of Botany. 2004;91:321-331.Floral development and molecular phylogeny support the generic status of Tasmannia (Winteraceae)