Allium Cepa L. (Liliaceae)
Onion is a herbaceous biennial composed largely of thickened leaf bases and a very short condensed stem at the base. The outermost leaf bases of the bulb are dry and pigmented and form a covering for the fleshy inner ones which are the food reserves. There is a great variation between cultivars in size, colour, pungency and quality of mature bulbs. The colour may be orange-yellow, reddish or purplish depending on the variety. There is also a small-bulbed variety called shallots considered by many taxonomists as a separate species A. ascalonicum. However, A.DE Candolle felt that "........it [shallot] is a modification of A. cepa, dating from about the beginning of the Christian era". Spring onion belongs to other species A. fistulosum L.
Health
benefits: Helps reduce risk of heart disease and stroke, natural antibiotic action,
relieves congestion in airways, can help bronchial congestion and aids cancer
resistance.
Globe onion should be clean and hard, and should have dry smooth skin. Avoid onions with developed seed stems, misshapen bulbs, or evidence of decay. Green onions should have fresh-looking green tops and a white neck; ones with yellowing, wilted, or discoloured tips should be avoided. Cooked onions can be eaten on their own, either steamed or boiled. Onion are usually used to flavour and enhance other vegetables and recipes.