Perennial herbs or deciduous shrubs or small trees; branches are often thick, with solid pith, and covered with lenticels. Leaves are opposite, compound (pinnate), and leaflets serrate. Flowers are white, small, numerous, 5-parted, 5 stamens, 3 styles, in broad clusters. Fruit is a berry-like drupe, 3-5 seeded. Native to the Northern Hemisphere, east and northwest Africa, South America, eastern Australia, and Tasmania.
Taxonomy: Richard Bolli published a monograph in 1994 titled, "Revision of the Genus Sambucus", in it he proposed the placement of 5 species of elderberry as subspecies of Sambucus nigra, including S. caerulea, Blue Elderberry, to S. nigra ssp. cerulea (note spelling) and S. canadensis, American Elderberry, to S. nigra ssp. canadensis. The Common or European Elderberry is S. nigra ssp. nigra or simply S. nigra. This change has been accepted by the Integrated Taxonomic Information System (ITIS), but certainly not all taxonomists, see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4859216/ .
Sambucus: a Latin word, possibly from sambuca, a kind of a harp made from Elderberry wood (S. nigra).