From The Collaborative International Dictionary of English v.0.48 [gcide]:
Impatiens \Im*pa"ti*ens\ ([i^]m*p[=a]"sh[i^]*[e^]nz), prop. n.
[L., impatient.] (Bot.)
A genus of plants, several species of which have very
beautiful flowers; -- so called because the elastic capsules
burst when touched, and scatter the seeds with considerable
force. Called also touch-me-not, jewelweed, and
snapweed. Impatiens Balsamina (sometimes called {lady's
slipper}) is the common garden balsam.
[1913 Webster]