Bachelor's buttons

Bachelor's buttons is a common name for several plant species bearing buttonlike heads of composite flowersThe New Educator Encyclopaedia: The Thoroughly Modern International Work Designed to Meet the Needs of Every Age (1952)

• 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.