(1):
(n.) A lady at a ball, who, either from choice, or because not asked to dance, remains a spectator.
(2):
(n.) In Australia, the desert poison bush (Gastrolobium grandiflorum); - called also native wallflower.
(3):
(n.) A perennial, cruciferous plant (Cheiranthus Cheiri), with sweet-scented flowers varying in color from yellow to orange and deep red. In Europe it very common on old walls.