Synonyms for Woolly Thistle (same or very similar meaning)
WordNet sense 1 (biennial Eurasian white hairy thistle having pale purple flowers; naturalized in North America):
cotton thistle, Onopordon acanthium, Onopordum acanthium, Scotch thistleWordNet sense 2 (thistle of western North America having white woolly leaves):
Cirsium flodmaniiFrom the ODE community, based on WordNetadd/edit