Merriam-Webster Collegiate Dictionary - touch-me-not

 noun  Etymology: from the bursting of the ripe pods and scattering of their seeds when touched  Date: 1659 either of two North American impatiens growing in moist areas: as  a. one (Impatiens capensis) typically having orange flowers spotted with reddish brown  b. one (I. pallida) having typically yellow flowers sometimes spotted with reddish brown