WordNet (r) 3.0 (2006):

Hieracium aurantiacum
    n 1: European hawkweed having flower heads with bright orange-
         red rays; a troublesome weed especially as naturalized in
         northeastern North America; sometimes placed in genus
         Hieracium [syn: orange hawkweed, Pilosella aurantiaca,
         Hieracium aurantiacum]