The family classification of the New Caledonian angiosperms has become more stable with the application of the APG system

Abstract

The era of molecular systematics has had a tremendous impact on taxonomy, with the increasing availability of phylogenetic trees allowing the recircumscription of higher taxa, particularly through the application of the monophyletic principle. Whether molecular phylogenetics has caused taxonomic instability has not been objectively assessed. Here, we used the flora of New Caledonia to monitor the evolution of the taxonomy of a tropical flora through four time windows from 1911 to 2024. This Pacific island's flora is renowned for its high species richness and endemism and includes 42% of the currently accepted flowering plant families, including the endemic Amborellaceae. We found that taxonomic changes, including changes in genera and families, have always been common, even in the pre-molecular era. If family changes were more important between 2001 and 2012, following the application of the classification proposed by the Angiosperm Phylogeny Group (APG), changes since then have been reduced to almost zero. Since the latest versions of the APG classification are almost identical, it seems that this classification can now be safely applied outside the world of scientific publication. Greater efforts are needed to achieve a stable generic classification, where collectives similar to APG could target such goals.