Origin of Veroniceae (Plantaginaceae, formerly Scrophulariaceae) on New Guinea

Members of Veroniceae are some of the most prominent members of the alpine vegetation of New Guinea. Generic classification suggests at least three origins because the endemic species of Veroniceae comprise two species of Veronica, twelve species of Parahebe, and the monotypic genus Detzneria. DNA sequence data (nr ITS region, plastid trnL-F region) have been analyzed using parsimony and maximum likelihood to test the hypothesis of three different introductions to New Guinea and their origin. The results largely confirm previous suggestions based on morphology, although lack of sufficient sequence variability in the Hebe complex does not allow definite conclusions. Veronica archboldii is closely related to the widespread V. serpyllifolia from the Northern Hemisphere. Parahebe vandewateri and P. albiflora are sisters and probably derived from New Zealand species, although not necessarily from species of Parahebe there. Finally, Detzneria tubata also belongs to the Hebe complex but has no clear affinities in this group. It may be a relict from the first immigration of Veronica species to the Southern Hemisphere. Reasons for different success of the three groups in speciating in New Guinea are discussed in the light of the known vegetation history of New Guinea.