Centaurea nigra

from WordNet (r) 3.0 (2006)

Centaurea nigra
    n 1: a weedy perennial with tough wiry stems and purple flowers;
         native to Europe but widely naturalized [syn: {lesser
         knapweed}, {black knapweed}, {hardheads}, {Centaurea
         nigra}]

from The Collaborative International Dictionary of English v.0.48

Ironheads \I"ron*heads`\, n. (Bot.)
   A European composite herb ({Centaurea nigra}); -- so called
   from the resemblance of its knobbed head to an iron ball
   fixed on a long handle. --Dr. Prior.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Knapweed \Knap"weed`\, n. (Bot.)
   The black centaury ({Centaurea nigra}); -- so called from the
   knoblike heads of flowers. Called also {bullweed}.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Matfelon \Mat"fel*on\, n. [W. madfelen.] (Bot.)
   The knapweed ({Centaurea nigra}).
   [1913 Webster]

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