Allium fistulosum, the Welsh onion, also commonly called bunching onion, long green onion, Japanese bunching onion, and spring onion, is a species of perennial plant, often considered to be a kind of scallion.

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.