Spanish button

Japanese: Spanish button（英語表記）Spanishbutton

...For potted plants and flower beds, dwarf species that bloom at 20 to 30 cm in height are used. There are 500 species of Centaurea (knapweed, hardhead, Spanish button), and among the annuals, sweet sultan ( C. moschata L.) and basket flower ( C. americana Nutt.) are grown as cut flowers and in flower beds, and yellow sultan ( C. sauveolens L.), which has a particularly strong fragrance, is grown in warm areas or in greenhouses for cut flowers, but if the drainage is not well maintained, it is prone to disease near the ground when it blooms. Among the perennials, golden cornflower (C. macrocephala Puschk.) is grown for cut flowers, and mountain bluet ( C. montana L.) is grown as a mountain plant. …

*Some of the terminology that mentions "Spanish button" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…鉢植や花壇のためには高さ20～30cmで咲く矮性（わいせい）種が用いられる。　ヤグルマギク属Centaurea(英名knapweed,hardhead,Spanish button)には500種もあるが，一年草ではニオイヤグルマ(スイート･サルタン)C.moschata L.(英名sweet sultan)やアザミヤグルマC.americana Nutt.(英名basket flower)が切花や花壇につくられ，とくに芳香の高いイェロー･サルタンC.sauveolens L.(英名yellow sultan)は切花の用に暖地やハウスで栽培されるが，排水よく管理しないと開花時に地際に発病が多い。多年草ではオウゴンヤグルマソウC.macrocephala Puschk.が切花にされ，C.montana L.(英名mountain bluet)が山草としてつくられる。…