Broccoli (Brassica oleracea var. italica) is an edible green plant in the cabbage family (family Brassicaceae, genus Brassica) whose large flowering head, stalk and small associated leaves are eaten as a vegetable. Broccoli is classified in the Italica cultivar group of the species Brassica oleracea. Broccoli has large flower heads, usually dark green, arranged in a tree-like structure branching out from a thick stalk which is usually light green. The mass of flower heads is surrounded by leaves. Broccoli resembles cauliflower, which is a different, but closely related cultivar group of the same Brassica species. It is eaten either raw or cooked. Broccoli is a particularly rich source of vitamin C and vitamin K. Contents of its characteristic sulfur-containing glucosinolate compounds, isothiocyanates and sulforaphane, are diminished by boiling, but are better preserved by steaming, microwaving or stir-frying. Rapini, sometimes called 'broccoli rabe, ' is a distinct species from broccoli, forming similar but smaller heads and is actually a type of turnip (Brassica rapa). Etymology The word broccoli comes from the Italian plural of broccolo, which means 'the flowering crest of a cabbage', and is the diminutive form of brocco, meaning 'small nail' or 'sprout'. Broccoli resulted from breeding of landrace Brassica crops in the northern Mediterranean starting in about the sixth century BCE. Broccoli has its origins in primitive cultivars grown in the Roman Empire and was most likely improved via artificial selection in the southern Italian Peninsula or in Sicily.