Molecular and morphological analysis shows this genus is most closely related to the genus Hicksbeachia, ancestors of the two genera having diverged around 15 million years ago in the Miocene.[3]
Species
The genus comprises two species which are native to northeastern Australia and New Guinea:[4]
^Mast, Austin R.; Willis, Crystal L.; Jones, Eric H.; Downs, Katherine M.; Weston, Peter H. (2008). "A smaller Macadamia from a more vagile tribe: inference of phylogenetic relationships, divergence times, and diaspore evolution in Macadamia and relatives (tribe Macadamieae; Proteaceae)". American Journal of Botany. 95 (7): 843–870. doi:10.3732/ajb.0700006. PMID21632410.
^Weston, Peter H.; Barker, Nigel P. (2008). "A new suprageneric classification of the Proteaceae, with an annotated checklist of genera". Telopea. 11 (3): 339. doi:10.7751/telopea20065733.