a natural family of monoecious trees and shrubs, including the genera Betula; Alnus; Carpinus; Corylus; Ostrya; and Ostryopsis.

monoecious trees and shrubs (including the genera Betula and Alnus and Carpinus and Corylus and Ostrya and Ostryopsis)

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.