Centaurea biebersteinii Dc.
Family: Asteraceae
spotted knapweed
[Acosta maculosa auct. non Holub,  more]
Centaurea biebersteinii image
Tina Ayers  
Biennial or short-lived perennial 3-15 dm, sparsely scabrous-puberulent, and with a thin and loose evanescent tomentum; lvs pinnatifid with narrow lobes, or the reduced ones of the infl entire; heads ter minating the numerous branches, constricted upward in life; invol 10-13 mm, its bracts striate, the middle and outer ones with short, dark, pectinate tip; fls pink-purple, the marginal ones enlarged; pappus to 3 mm, or rarely none; 2n=18, 36. Fields, roadsides, and waste places; native of Europe, now commonly established in our range and westward. June-Oct. (C. rhenana; ? C. stoebe L., an older name)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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