a common yellow-flowered European perennial plant of the buttercup family: Ranunculus ficaria. Also called lesser celandine
There's a flower that shall be mine, ’tis the little celandine — Wordsworth
a yellow-flowered biennial plant of the poppy family: Chelidonium majus. Also called greater celandine
Middle English celidoine via Old French and Latin from Greek chelidonios, from chelidōn swallow. The flowering season of the plant was believed to coincide with the arrival and departure of migrating swallows