Scallions (also known as spring onions or green onions) are vegetables derived from various species in the genus allium. scallions generally have a milder taste than most onions and their close relatives include garlic, shallot, leek, chive, and chinese onions.although the bulbs of many allium species are used as food, the defining characteristic of scallion species is that they lack a fully developed bulb. instead the allium species referred to as scallions make use of the hollow, tubular green leaves growing directly from the bulb. these leaves are used as a vegetable and can be eaten either raw or cooked. often the leaves are chopped into other dishes and used as garnishes.

Source: Wikipedia