= nonnative, planted and a wildland component, commonly "escapes" cultivation
= nonnative, planted, generally not considered a wildland component or invasive
= a North American native, may naturalize outside its native range
Genus: Corylus
    Corylus americana - American hazel
    Corylus avellana - common filbert
    Corylus colurna - Turkish hazel
    Corylus cornuta - beaked hazel