Plant of the day is: Dicrostachys cinerea or sickle bush
Awww yeah.
There are actually a whole slew of common names for this, including: Bell mimosa, Chinese lantern tree, and Kalahari Christmas tree.
Range: Originally a native of South Africa, it has been flung far and wide through tropical climates around the world. In the Caribbean it is a serious invasive problem and attempts are being made to transform it into a viable source of biofuel. It occupies about 5 million acres of agricultural land. I can't even wrap my head around that number. It is huuuuge.
A lil taxonomy: This is a member of the Fabaceae or legume family. It fixes nitrogen, so at least it lends something to it's aggressiveness. Many members of this family make some extremely successful and extremely invasive, gotta be vigilant. But I digress, Dicrostachys is a monotypic genus which means it only has the one species. It's really kind of a neat plant. Dicrostachys means two colored inflorescence for all practical purposes. You can see why. I like it, I used to DJ as Dichromatic but nobody could pronounce it. It's like: die-chrome-attic. Or in this instance: die-crow-stack-eaze.
Description: Like many legumes, this plant also features a bi-pinnate leaf. It is a woody semi deciduous to deciduous tree that is adapted to a wide range of environments. The best key for ID here is the fantastical flowers which you will note are two colors. The top purple flowers are actually sterile, while the lower yellowish ones are the fertile flowers (yes the whole inflorescence is a collection of flowers). The fruits that arise are green curly pods with about 4 seeds in them that eventually turn brown and fall to the ground. Also has some fairly nasty spines at nodes.
Chinese lantern seems a stretch.
Musings: Really, I would have to say its adaptability is the reason it is such a pest really. I find it interesting that human interests often align against the best workable models nature comes up with for plant design. I always try to remember, when I'm detering all these invasives, not to be cranky at the plant, but for the moron that put it there.
You can see why it is invasive. Does well.