This plant has started growing in my bougainvillea and there's some debate going on in the house whether it is a weed, or part of the bougainvillea, perhaps the male part. I'm unable to find any pictures of bougainvillea's that have this in them.
Plant in question:
Bougainvillea:
It looks like a mint or a very closely related labitae. Even the flower spike looks like mint. Is the stem squarish?
In any case it is certainly not part of your bougainvillea.
After some further research, and with the help of @Escoce's and @Bamboo's answers, I believe this is a Sweet Almond Bush.
©Dave's Garden / http://pics.davesgarden.com/pics/2006/05/07/aprilwillis/bfe970.jpg
Agree with @Escoce's answer, point given, but note also there is no separate 'male part' in Bougainvillea, the flowers contain both male and female components, although they are not self fertile. This is definitely a separate plant growing behind and through your Bougainvillea.
