bract
The bracts of the poinsettia are large and red; the flowers in the center are insignificant in comparison.
A bract is a modified leaf found on a flower stalk or the flower base. Bracts are usually small and scalelike; however, in some species, such dogwood, poinsettia, and Bourgainvillea they are large and highly colored to attract insects and may be mistaken for actual flowers.
A series of bracts beneath or around a flower or flower cluster is called an involucre.
