First indisputable fossil Ilex (Aquifoliales: Aquifoliaceae) flower found in Baltic amber

The genus Ilex (holly) in the monotypic family Aquifoliaceae contains more than 600 species distributed worldwide. Pollen fossils and macrofossils of fruits of Ilex are known from the late Cretaceous (90 Ma) and verified leaves from the upper Miocene (10 Ma), but until now only a few more or less incomplete flower fossils have been suggested as referable to this genus. This paper reviews the fossil flowers earlier attributed to Ilex and presents a complete and indisputable staminate Ilex flower from Baltic amber (34-38 Ma) examined in detail with synchrotron X-ray tomography. This finding may challenge the hypothesis of late Neogene dispersal of the genus from a center of origin in subtropical East Asia.