Bachelor's buttons

Bachelor's buttons is a common name for several plant species:
 * Gomphrena canescens, native to Australia.
 * Gomphrena globosa, native to Brazil, Panama and Guatemala.
 * Centaurea cyanus, native to Europe, including the British Isles and cultivated as an annual ornamental plant.
 * Centaurea montana, native to Europe, excluding the British Isles, and cultivated as a perennial ornamental plant.
 * Kerria japonica 'Pleniflora', a double-flowered cultivar of a species native to China, Japan and Korea.
 * Ranunculus aconitifolius, native to central Europe.