Know your Onions

  • Onion is a term used for many plants in the genus Allium. 

  • They are known by the common name "onion" but, used without qualifiers, it usually refers to Allium cepa.

  • Allium cepa is also known as the "garden onion" or "bulb" onion.

  • It is grown underground by the plant as a vertical shoot that is used for food storage, leading to the possibility of confusion with a tuber, which it is not.

  • Allium cepa is known only in cultivation, but related wild species occur in Central Asia. 

  • The most closely related species include Allium vavilovii (Popov & Vved.) and Allium asarense (R.M. Fritsch & Matin) from Iran. However, Zohary and Hopf warn that "there are doubts whether the vavilovii collections tested represent genuine wild material or only feral derivatives of the crop."