Bougainvillea shows its beautiful red, pink, orange, or purple color during blooming.
However, casual observers may never actually see the blooms. The color comes from the modified leaves of the plant (called bracts). The actual blooms are very small and usually are either white or light yellow. They extend out in the middle of a group of bracts.
The plant is also known as the Paper Flower (because of the paper-like texture and appearance of the bracts).
At the time the above photo was taken, the blooms had not come out. However, the photo below (taken three days later) shows the tiny blooms.
Allergy sufferers take note: The tiny flowers of the produce less pollen and therefore are less likely to provoke an attack than many other flowers (c.f. BGI-USA).
To read more about the Bougainvillea, (actually more than most people would read in a single setting), visit the BGI website.