Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae) 1

A study of the Australasian genus Dracophyllum (Ericaceae) reveals that its species richness and diversity peak in New Zealand, with evolutionary roots tracing back to the Eocene. Phylogenetic analyses using chloroplast genes matK and rbcL showed that tribe Richeeae diverged at least 33.3 million years ago, with a crown radiation during the Early Miocene (16.5 Ma). This period aligns with Australia's aridification, leading to two distinct lineages: one isolated in southern Western Australia (Sphenotoma) and another spanning eastern Australia, Lord Howe Island, New Caledonia, and New Zealand (Dracophyllum and Richea). The study also documents two independent long-distance dispersal events from Australia to New Caledonia and New Zealand during the Late Miocene to Early Pliocene, with rapid species radiation occurring within the last 3–6 million years. Additionally, it suggests that Dracophyllum is paraphyletic and Richea polyphyletic, necessitating taxonomic revision.

Wagstaff, S. J., Dawson, M. I., Venter, S., Munzinger, J., Crayn, D. M., Steane, D. A., & Lemson, K. L. (2010). Origin, Diversification, and Classification of the Australasian Genus Dracophyllum (Richeeae, Ericaceae) ¹. Annals of the Missouri Botanical Garden, 97(2), 235–258. https://doi.org/10.3417/2008130