Sitka Alder, Slide Alder, Wavy-leaved Alder: Alnus alnobetula ssp. sinuata (Synonyms: Alnus crispa ssp. laciniata, Alnus crispa ssp. sinuata, Alnus sinuata, Alnus sitchensis, Alnus viridis ssp. fruticosa, Alnus viridis ssp. sinuata, Alnus viridis var. sinuata, Duschekia sinuata) -
Gray Alder, Mountain Alder, Thinleaf Alder, Thin-leaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia) -
California Alder, White Alder: Alnus rhombifolia (Synonym: Alnus rhombifolia var. bernardina) -
Oregon Alder, Red Alder: Alnus rubra (Synonyms: Alnus oregona, Alnus oregona var. oregona, Alnus oregona var. pinnatisecta, Alnus rubra var. pinnatisecta) -