Spring onion

Scallions are edible vegetables of various species in the genus Allium. Scallions generally have a milder taste than most onions. Their close relatives include garlic, shallots, leeks, chives, and Chinese onions. Although people use the bulbs of many Allium species as food, the defining characteristic of scallion species is that they lack a fully-developed bulb. Instead the Allium species referred to as scallions provide 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 various dishes and used as garnishes.

Source: Wikipedia