This is the scientific name for the sensitive plant, a.k.a. humble plant, shame plant, or touch-me-not. It is, according to Wikipedia, native to Central- and South America, but is now considered a pan-tropical weed, grown for its curiosity value: the compound leaves fold inward and droop when touched or shaken, defending themselves from harm, and reopen a few minutes later. The foliage also closes during darkness and reopens in light.
The mimosa pudica also has a beautiful, delicate-looking flower. It was a pleasant surprise to look down one day and see these blooming.