Geographic relationships of Malagasy Annonaceae

The pantropical family Annonaceae (130 genera) is relatively poorly represented in Madagascar, with only nine genera. A cladistic analysis of the principal genera or groups of Annonaceae, using 78 macro- and micro-morphological characters, allows the Malagasy taxa to be placed in major lines of the family. It confirms the primitive character of the one endemic genus, Ambavia, which is near the base of the family and belongs to a small clade with other members in South America, Africa, and Asia, suggesting an early origin when exchanges between Laurasia and Gondwana were still easy (Early Cretaceous?). Isolona (Africa, Madagascar) and Annona (Africa, America), which are nested among other African-American groups, may be derived from a radiation in Africa and South America when the South Atlantic was narrower (Late Cretaceous?). The Asian-Malagasy Polyalthia group is nested among American << malmeoids, >> suggesting an African-South American origin followed by dispersal to Madagascar and then Asia, perhaps by way of India (Early Tertiary?). Artabotrys, Uvaria, and Monanthotaxis, African-Asian genera related to African-South American taxa, and the only pantropical genus, Xylopia, linked with Cananga (Asia) and Neostenanthera (Africa), may have had a similar history.