Verneda hermaphroditica gen. & sp. nov.: A new flower head from the early Late Cretaceous (middle Cenomanian) of southeastern France
Résumé
Spherical flower heads have often been reported from the late Early and Late Cretaceous of Asia and North America,
but are rare in Europe. Palaeobotanists have included them in Altingiaceae and Hamamelidaceae (Saxifragales, basal core
eudicots), and Platanaceae (Proteales, basal eudicots). We report newly collected flower heads from the Cenomanian of southeastern
France. They are examined using scanning electron microscopy and propagation phase-contrast X-ray synchrotron
microtomography with a voxel size down to 0.7 μm. They are described and compared with 95 living angiosperms, which include
basal eudicots, basal rosids and basal asterids, based on a cladistic analysis of 64 characters. Verneda hermaphroditica gen. &
sp. nov. consists of flower heads with around one hundred actinomorphic, pentamerous, bisexual flowers. The androecium has
united filaments but free tetrasporangiate anthers. Pollen grains are tricolpate and reticulate. The gynoecium is eusyncarpous
and pentalocular. Each of the five carpels contains a single ovule/seed. Cladistic analysis suggests that Verneda hermaphroditica
is sister to Platanaceae. It cannot, however, be included in this family because characters such as basally fused stamen
filaments and eusyncarpous gynoecium are absent in living Platanaceae.