Snapdragons

Any of several varieties of garden flowers, typically red or golden yellow, or a combination of the two colours. The petals of these flowers can grow into intricate lobed shapes, with some varieties fancifully recalling the jaws of a fantastical beast, hence the name 'snapdragon'. They were known in the Shire, and grew in the garden at Bag End. It was perhaps this connection that inspired Bilbo to compare some of Gandalf's famed fireworks to the form of snapdragons (indeed, he was in his garden at the time, so may actually have been looking at his snapdragons as he made the comment).

Bilbo made that comparison in III 2941, but his comments prefigured his own eleventy-first Birthday Party sixty years later. At that Party, Gandalf created a firework recapturing the shape of an actual snapping Dragon: that of Smaug the defeated Dragon of Erebor.