'flower-of-an-hour' definitions:
Definition of 'flower-of-an-hour'
(from WordNet)
noun
Annual weedy herb with ephemeral yellow purple-eyed flowers; Old World tropics; naturalized as a weed in North America [syn: flower-of-an-hour, flowers-of-an-hour, bladder ketmia, black-eyed Susan, Hibiscus trionum]