Synonyms for Cornflower (same or very similar meaning)
WordNet sense 1 (plant of southern and southeastern United States grown for its yellow flowers that can be dried):
strawflower, Uvularia grandifloraWordNet sense 2 (an annual Eurasian plant cultivated in North America having showy heads of blue or purple or pink or white flowers):
bluebottle, bachelor's button, Centaurea cyanusFrom the ODE community, based on WordNetadd/edit