Allium cepa, commonly known as onion, is a biennial herbaceous plant belonging to the Amaryllidaceae family. It is the most widely cultivated species of the Allium genus, which also contains several species called “onions” that are grown for food. Examples of these are the green onion (Allium fistulosum), the shallot (Allium ascalonicum) and the leaf onion (chives or ciboulette, Allium schoenoprasum).