Sierra magazine selected "7 of the World's Strangest Flowers." Above is video of the Touch-Me-Not, native to Central and South America but now growing many other places:

You might easily overlook this herb, with its dainty pink flowers and delicate, fern-like leaves. The mimosa pudica doesn’t just look demure, though. Barely touching its leaves causes them to fold inward and droop downward—hence the flower’s species name, pudica, Latin for “shy, bashful, or shrinking,” as well as its nicknames, “touch-me-not” and “shy plant.” The leaves usually reopen in a few minutes. Other stimuli, including warming and shaking the plant, produce the same phenomenon. The leaves fold and wilt in the evening, too, but they stay that way until sunrise…
"7 of the World's Strangest Flowers" (Thanks, Orli Cotel!)