any of a genus (Gerardia) of American plants of the figwort family, with showy yellow, white, or pinkish flowers: it is sometimes parasitic on roots
See gerardia in American Heritage Dictionary 4
(jə-rärˈdē-ə)
noun
Any of various herbaceous, root-parasitizing plants of the genus Agalinus, native to temperate regions of the Western Hemisphere, having large pink, purple, or white flowers with yellow markings in some species.