The Bougainvillea is a very common, very thorny shub/ vine here in Brisbane, Australia.
It is known for is "showy flowers" and utilised to cover fences and arbour's.
The truth is that what most people think are the flowers are just modified leaves (Bracts are what they are referred to by botanists.)
Native to the central America areas, this specimen is in Brisbane, Australia.
If you look past the bracts you can see the true flower parts (stamens and anthers)
I would assume the plant evolved to have these modified leaves to attract insects and other animals to the pollen.
NOTE: If you want this plant to look neat and tidy keep the maintenance up!!!
It is a complete pain in the arse if it gets out of control 😉
Happy gardening,