#knapweed  any of various plants of the genus Centaurea having purple thistlelike flowers
  supertype:  centaury  any plant of the genus Centaurea
  subtype:  slender_knapweed__slenderknapweed  a variety of knapweed
  subtype:  Jersey_knapweed  a variety of knapweed
  subtype:  lesser_knapweed__black_knapweed__blackknapweed__hardheads__hardhead__Centaurea_nigra  a weedy perennial with tough wiry stems and purple flowers; native to Europe but widely naturalized
  subtype:  great_knapweed__greatknapweed__greater_knapweed__greaterknapweed__Centaurea_scabiosa  tall European perennial having purple flower heads

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