Abstract: The vessel elements in 77 species of 36 genera of Chinese Ranunculaceae were studied. The vessel elements of Ranunculaceae could be divided into primitive and more specialized groups on the basis of their morphological characters through clustering analysis. The most primitive type of the vessel elements was seen in Asteropyrum, and some vessel elements were considered more primitive, as in Paeonia, Trollius, Actaea, Helleborus, Souliea, Calathodes, Beesia, Caltha, Coptis, Kingdonia, Circaeaster, Adonis, Hepatica, than others. There was a marked difference between Paeonia and other genera of Ranunculaceae. The vessel elements of Paeonioideae and Helleboroideae with follicles were more primitive than Ranunculoideae with achenes. In Thalictroideae, .the vessel elements of Thalictrum with achenes were more specialized than other genera with follicles. All these findings coincided with the evolution of fruits. The character of evolution of vessel elements ran parallel with that of other parts of plant (flower, carpel, petiole, venation). The features of vessel elements in the same genus were at similar evolutional level, however, some difference between species do exist.

Key words: Ranunculaceae, Vessel elements, Evolution