Knautia arvensis (L.) Duby
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Authority
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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Family
Dipsacaceae
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Scientific Name
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Description
Species Description - Taprooted, hairy perennial 3–10 dm, lowest lvs usually merely coarsely toothed, the others ± deeply pinnatifid with narrow lateral and broader terminal segments, to 2.5 cm, reduced upwards; heads 1.5–4 cm thick; involucral bracts 8–12 mm; cal 3–4 mm; the 8–12 teeth bristle-like; cor lilac-purple, the marginal ones the largest; fr 5–6 mm, densely hairy; 2n=20, 40, 43, 46. A European weed, naturalized from Nf. and Que. to N.J. and W.Va. June–Sept. (Scabiosa a.)
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Common Names
blue buttons