genus of mostly woody relatively primitive dicotyledonous flowering plants with flowers often unisexual and often borne in catkins

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

any of several shrubs or small trees of the genus Corylus bearing edible nuts enclosed in a leafy husk

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

any of several shrubs or small trees of the genus Corylus bearing edible nuts enclosed in a leafy husk