The two parts of the broccoli plant (Brassica oleracea) that are typically eaten are known as florets and stems. The corresponding plant parts from which they are derived are the immature green flowers and the flower stalks.
Over time, humans have selected for enlarged plant parts of domesticated species. Some of the parts that are typically enlarged include fruit and seeds. In the case of the B. oleracea species, several crops were derived, including cabbage, broccoli and Brussels sprouts. Different plant parts were selected for enlargement, depending on the cultivar – the leaves for cabbage, the immature flowers and stems for broccoli, and the axillary buds for Brussels sprouts.