This variety of onions is generally characterized by dark red bulbs and are globular and round in shape. They have tight skin and are moderately pungent. The onion crop matures in 90-100 days after transplanting. An onion, also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus Allium. The shallot is a botanical variety of the onion which was classified as a separate species until 2011.