Abstract: In the present thesis, a detailed review of the literature was given on the Betulaceae. Some new data was provided based on the author’s studies in order to analyze various characters, such as inflorescence, flower, pollen and leaf epidermis, among the genera treated. The polarity of the characters was determined according to the criteria of outgroup comparison and compatibility analysis. A cladistic analysis was made using the methods of Maximal Same Steps and Minimal Parallel Evolution developed by Xu (1993). The generic distributions in both modern and fossil times were outlined, and their distribution center, place and time of origin and the way of dispersal were discussed. An attempt was made to discuss early differentiation, geographical radiation and morphological evolution of the family on the background of paleogeography and paleoclimatology, tracing back as far as the Late Cretaceous and Early Tertiary. Finally, supraspecific taxa, from section to tribe, were systematically arranged.

Key words: Betulaceae, Cladistic analysis, Distribution, Evolution, Systematic treatment