Betulaceae, or the Birch Family, includes six genera of deciduous nut-bearing trees and shrubs, including the birches, alders, hazels, hornbeams and hop-hornbeams, numbering about 130 species. They are mostly natives of the temperate Northern Hemisphere, with a few species reaching the Southern Hemisphere in the Andes in South America. In the past, the family was often divided into two families, Betulaceae (Alnus, Betula) and Corylaceae (the rest); however, recent treatments, including the Angi… (More on Betulaceae)