Fruits of Tetrapterys (Malpighiaceae) from the Oligocene of Hungary and Slovenia.

Propeller-like winged fruits of Tetrapterys harpyiarum Unger from the Oligocene of Sotzka, Budapest, Eger-Vécsey valley, and a new occurrence at Eger-Kiseged, were reinvestigated and compared in detail with extant species of Tetrapterys (Malpighiaceae) and with other dicotyledonous genera with four winged fruits. T. harpyiarum fruits are bilaterally symmetrical, consisting of a globose nut surrounded by four elongate wings with parallel venation. Tetrapterys is now distributed only in tropical America and this implies that there was an opportunity for Tetrapterys to spread between the Partethys region and the New World during the Tertiary.