Broccoli is a plant in the cabbage family, whose large flower head is used as a vegetable; it is classified in the Italica cultivar group of the species Brassica oleracea.  It has large flower heads, usually green in color, arranged in a tree-like fashion on branches sprouting from a thick, edible stalk. The mass of broccoli flower heads is surrounded by leaves. Broccoli most closely resembles cauliflower, which is a different cultivar group of the same species.

The plant evolved from a wild cabbage plant on the continent of Europe. Indications point to the vegetable's being known 2,000 years ago. Since the Roman Empire, the plant has been considered a uniquely valuable food among Italians. Broccoli was grown at Antwerp whence it was taken to England by the sculptor Peter Scheemakers, according to a biographical note by J. T. Smith. The plant was first introduced to the United States by Italian immigrants but did not become widely known until the 1920s.