Diversity in the vessel elements of Ranunculaceae‐Paeoniaceae complex

Vessel members of the Ranunculaceae and Paeoniaceae are illustrated and described. On the basis of the size the vessels of both the families can be categorised into: long, medium and short. The vessels of Ranunculaceae are characterised by commonly simple and occasionally or rarely scalariform, and those of Paeoniaceae by predominently foraminate (ephedroid) occasionally scalariform and rarely simple perforation plates. The noteworthy feature is the occurrence of two different types of perforation plates (simple and scalariform) at the opposite end of the same vessel. The side wall thickening of the vessels is either simple pitted, border pitted or spiral in the Ranunculaceae and in the Peaoniaceae strictly simple pitted. The structure of vessel elements of these two families definitely justify the separation of the Paeoniaceae from the Ranunculaceae.