Flower Buds Confirmed in the Early Cretaceous of China.

Simple Summary: Flowers are attractive to many people mainly due to their colourful and conspicuous perianth, which is closely related to successful insect pollination in extant angiosperms. The Lower Cretaceous Yixian Formation (125 million years ago) in Northeastern China is famous for its great diversity of early angiosperms. However, unlike typical flowers in extant angiosperms, the previously documented fossil flowers are usually famous for their "nakedness", namely, they do not have typical petals (corolla), suggesting a pollination strategy for early angiosperms that is different than that of the extant angiosperms. However, without fossil evidence, whether there are petals (corolla) and whether androecium and gynoecium are protected in early flowers are rarely addressed questions. Here, we document a flower bud fossil, Archaebuda cretaceae sp. nov., from the Yixian Formation, which is the second case in the Formation. While reinforcing the truthful occurrence of fragile flower buds in the Early Cretaceous, new fossil evidence demonstrates the existence of gynoecium and possible androecium within the flower bud, suggestive of the possible bisexuality and the protection function of petals in Archaebuda, just as in extant flowers. In addition, it is very likely that conspicuous petals may have played an important role in attracting insects for successful pollination in early angiosperms. Therefore, the occurrence of petals (corolla) in Archaebuda cretaceae sheds a new light on the reproduction of early angiosperms. The Yixian Formation (Lower Cretaceous) in China is famous worldwide for its fossils of early angiosperms, but there has been only one record of flower buds (Archaebuda lingyuanensis) hitherto, in which only the surface of the flower bud was documented while no internal details were known. Such a partial knowledge of flower buds hinders our understanding of the evolution of flowers, and this knowledge lacuna needs to be filled. Our new specimen was collected from an outcrop of the Yixian Formation (Barremian–Aptian, Lower Cretaceous) near Dawangzhangzi, Lingyuan, Liaoning, China. Our observations reveal a new fossil flower bud, Archaebuda cretaceae sp. nov., from the Lower Cretaceous of China. This new record of Archaebuda in the Yixian Formation not only confirms the truthful existence of the expected gynoecium (plus possible androecium) in a flower bud but also underscores the occurrence of typical flowers in the Early Cretaceous. This new information adds first-hand data to flower sexuality, pollination, and evolution. [ABSTRACT FROM AUTHOR]