XVI International Botanical Congess

The Betulaceae comprises 6 genera (Betula, Alnus, Carpinus, Corylus, Ostrya and Ostryopsis) distributed throughout the Northern Hemisphere except Ostryopsis which is endemic to eastern Asia. A study of the evolution and variation of the 5S rDNA unit at the populational level was performed within Corylus cornuta, using several populations. The phylogenetic analysis of the Betulaceae based on the gene and spacer sequences of the 5s rDNA unit included all 6 genera and members of each section within genera. Preliminary analyses support the division of the family into two subfamilies, Betuloideae and Coryloideae. Within the latter, the two traditionnaly recognized tribes, Coryleae (Corylus) and Carpineae (Ostryopsis, Ostrya, Carpinus), are also supported.