Onion

The onion is any of a variety of plants in the genus Allium, specifically Allium cepa. Allium cepa is also known as the “garden onion” or “bulb” onion. Above ground, the onion shows only a single vertical shoot; the bulb grows underground, and is used for energy storage, leading to the possibility of confusion with a tuber, which it is not. It is a close relative to garlic. 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 A. vavilovii collections tested represent genuine wild material or only feral derivatives of the crop.”