Dutchman's breeches

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun plural A woodland plant (Dicentra cucullaria) of the northern United States and southern Canada, having finely divided leaves and yellowish-white flowers with two spurs.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot.) a delicate perennial spring-flowering herb (Dicentra cucullaria) of eastern U.S., having peculiar double-spurred white flowers. See Illust. of dicentra