Henrik Balslev

To most palm systematists it came as a surprise when molecular evidence pointed to a sister group relationship between the tribe Ceroxyleae in the subfamily Ceroxyloideae and the Phytelephantoid palms formerly referred to a subfamily of their own, now placed in the tribe Phytelepheae. Here we compare floral ontogenetic sequences of representatives of the two groups to identify shared and distinguishing traits. The Phytelephantoid palms probably originated 25–15 millions years ago in early Miocene, which is more recent than has been suggested previously. They are characterized by a number of synapomorphies in the inflorescences and flowers, so unusual within the palms that they have clouded the interpretation of ancestral relationships for centuries. We suggest that the saltatory evolution of the Phytelepheae within Ceroxyloideae is a striking example of paedomorphosis within the Monocotyledons.