Blue Elder, Blue Elderberry, Southwestern Elderberry: Sambucus mexicana ssp. cerulea (Synonyms: Sambucus caerulea, Sambucus caerulea var. neomexicana, Sambucus caerulea var. velutina, Sambucus cerulea, Sambucus cerulea var. cerulea, Sambucus cerulea var. neomexicana, Sambucus cerulea var. velutina, Sambucus glauca, Sambucus mexicana ssp. caerulea, Sambucus mexicana ssp. cerulea, Sambucus mexicana var. caerulea, Sambucus neomexicana, Sambucus neomexicana var. vestita, Sambucus nigra ssp. caerulea, Sambucus nigra ssp. cerulea) - Berries bluish, covered with a glaucous or grayish coat of yeast. Inflorescence flat-topped.
European Black Elderberry: Sambucus nigra -
Pacific Red Elderberry, Red Elderberry: Sambucus racemosa var. arborescens (Synonyms: Sambucus callicarpa, Sambucus microbotrys, Sambucus pubens, Sambucus pubens var. arborescens, Sambucus racemosa ssp. pubens, Sambucus racemosa ssp. pubens var. arborescens, Sambucus racemosa var. laciniata, Sambucus racemosa var. leucocarpa, Sambucus racemosa var. microbotrys, Sambucus racemosa var. pubens, Sambucus racemosa var. racemosa) - Generally found from the Cascade Mts. west to the coast, but it is occasionally found east of the mountains, at least in Oregon (Unless samples were really misidentified black elderberry).
Black Elderberry: Sambucus racemosa var. melanocarpa (Synonyms: Sambucus melanocarpa, Sambucus racemosa ssp. pubens var. melanocarpa) - Berries reddish to purplish-black. Inflorescence is widely conical in shape.