Centaurea cyanus
"Centaurea cyanus" is native to temperate Europe, but is widely naturalized outside its native range. It has been present in the British Isles as an archaeophyte (ancient introduction) since the Iron Age. In the United Kingdom, it has declined from 264 sites to just 3 sites in the last 50 years. In reaction to this, the conservation charity Plantlife named it as one of 101 species it would actively work to bring 'back from the brink'. In the County Clare (VC H9) in Ireland, "Centaurea cyanus" is recorded in arable fields as very rare and almost extinct, while in the North-East of Ireland, it was abundant before the 1930s.