Abstract:Souliea vaginata (Maxim. ) Franch. is the only member of Souliea Franch. belonging to Ranunculaceae and endemic to East Asia. The vessel elements and their perforation plates in the secondary xylem of stem of the species were observed under SEM in order to provide new anatomical evidence for a better understanding of the taxonomy and systematic position of the genus. The results showed that the reticulate ( ephedroid) , scalariform, reticulate- scalariform, reticulatescalariform- simple, and scalariform- simple perforation plates of the vessel elements were found for the first time in Ranunculaceae. The mult-i perforation plate of the end-wall and the latera-l wall perforation plates have been observed and the pit membrane remnants in the different perforation plates were also described. The evolution of the perforation plates of the vessel elements and the systematic position of genus Souliea were discussed in the paper based on the present observation.