Development of flowers and inflorescences of Circaeaster (Circaeasteraceae, Ranunculales)

The flower organs of Circaeaster are spiral in origin. The primordia of the tepals, stamens and carpels are almost the same in shape and size in early development. Carpel conduplication takes place only in the middle part of the carpel. The basal part of the carpel differentiates into a short stalk and the upper part into the style and the stigma. Flower development is similar to that of Kingdonia. Floral development of Circaeaster is compared with that of other Ranunculales.