From WordNet (r) 3.0 (2006) :
Johnny-jump-up
n 1: a common and long cultivated European herb from which most
common garden pansies are derived [syn: wild pansy,
Johnny-jump-up, heartsease, love-in-idleness, pink
of my John, Viola tricolor]
2: common violet of the eastern United States with large pale
blue or purple flowers resembling pansies [syn: bird's-foot
violet, pansy violet, Johnny-jump-up, wood violet,
Viola pedata]