Allium fistulosum
Allium fistulosum, the Welsh onion, also commonly called bunching onion, long green onion, Japanese bunching onion, stone leek, rock onion and spring onion, is a species of perennial plant, often considered to be a kind of scallion. The species is very similar in taste and odor to the related common onion, Allium cepa, and hybrids between the two (tree onions) exist.