All recent molecular phylogenetic analyses restrict Magnoliales to a monophyletic order of six families, whose closest relatives are Laurales, Winterales, and Piperales. We present a morphological cladistic study of all 20 genera of Myristicaceae and a broad sample of outgroups, emphasizing the contribution of palynological characters. This analysis placed the Malagasy genus Mauloutchia at the base of Myristicaceae. However, a detailed species-level study of Mauloutchia reveals unexpected intrageneric variation for the most important characters in the family (including stamen fusion, exine structure, and aril development), calling into question the putative primitiveness of this enigmatic genus. In addition, we generated sequences of the trnK intron (including matK), the trnL intron, the trnL-trnF spacer, and the ndhF gene from all families of Magnoliales (including 15 genera of Myristicaceae) and major lineages of all three related orders. Parsimony and maximum-likelihood analyses of these data sets strongly support a basal position of Myristicaceae in Magnoliales and a sister-group relationship between Eupomatia and Annonaceae, as suggested in higher-level angiosperm analyses with less intensive sampling in Magnoliales. Within Myristicaceae, these data support several groups found in the morphological analyses, especially an Asian clade including Myristica and Knema, but not the basal position of Mauloutchia, which belongs instead to an Afro-Malagasy clade. However, these usually fast-evolving sequences provide much less informative variation than expected for this diverse and widely distributed family. Annonaceae show at least three times as much variation as Myristicaceae in the same genes. Whether these results indicate an unexpectedly recent origin of Myristicaceae or major changes in molecular rates during the history of Magnoliales remains unclear. In either case, rooting of Myristicaceae using DNA sequences turns out to be a difficult problem, due to the very long stem branch leading to the extant family.

Key words: Magnoliales, morphology, Myristicaceae, ndhF, trnK intron, trnL