Atlas of foliar surface features in woody plants,IX. Betulaceae of eastern United States

Scanning electron microscopy was used to examine foliar surface features such as cuticular patterns, epicuticular wax, and trichome types in species ofAlnus, Betula, Carpinus, Corylus, andOstrya. Six trichome types are recognized in this survey, four non-glandular (acicular, filiform, aduncate, subulate) and two glandular (stipitate gland and peltate scale). The distribution of these trichomes among the genera supports the recognition of two tribes, Betuleae (Alnus andBetula) and Coryleae (Carpinus, Corylus, andOstrya). Trichome morphology can be an important supportive taxonomic character in determining evolutionary relationships.