Source : WordNet®

woolly thistle
     n 1: biennial Eurasian white hairy thistle having pale purple
          flowers; naturalized in North America [syn: {cotton
          thistle}, {Scotch thistle}, {Onopordum acanthium}, {Onopordon
          acanthium}]
     2: thistle of western North America having white woolly leaves
        [syn: {Cirsium flodmanii}]