Expanded generic concepts for Kermadecia and Persoonia, Proteaceae of New Caledonia and neighboring islands

Proteaceae, the Macadamia nut family, are diverse in New Caledonia with c. 50 species distributed in nine genera in tribes Embothrieae, Macadamieae, Persoonieae, and Roupaleae, where they represent an important component of the rainforest and particularly the maquis. The family is also represented by a few species in the neighboring archipelagos of Vanuatu and Fiji, which marks the eastern limit of its distribution in the Pacific. Here, we address some issues regarding generic limits within Pacific Proteaceae, using new molecular data and a review of morphology. The generic limits within the tribe Macadamieae have long been problematic, particularly amongst Kermadecia, Sleumerodendron, and Turrillia, which are part of the subtribe Gevuininae. Molecular phylogenetics shows that they form a monophyletic group, while morphological data indicate that they are only weakly differentiated. We conclude that they are better treated as a single genus, Kermadecia, as has been done previously, with eight species. Kermadecia elliptica is placed in synonymy under K. rotundifolia for the first time, and several names in the genus are lectotypified. As previously observed, we found that the New Caledonian endemic Garnieria spathulifolia is nested in Persoonia (tribe Persoonieae) from which it differs only by the number of ovules and is therefore transferred to it and a lectotype is designated.

Automated summary

Proteaceae, including the Macadamia nut family, have a wide variety of species in New Caledonia, with some also found in neighboring archipelagos. New molecular data and a review of morphology have helped resolve issues regarding generic limits within Pacific Proteaceae. Specifically, the Kermadecia, Sleumerodendron, and Turrillia genera within the Macadamieae tribe have been found to be better treated as a single genus, Kermadecia, with eight species. Additionally, the New Caledonian Garnieria spathulifolia has been transferred to the Persoonia genus.