Russian knapweed (Centaurea repens)
Roots: Extensive, widely spreading, black, may penetrate over 8 feet.
Stems: Erect, openly branched.
Leaves: Alternate, clasping, lower leaves deeply lobed, upper leaves entire or serrated.
Seed: Small, oval.
Flowers: Numerous, disc shaped, pink to purplish, bracts below the flower have pointed papery sheaths.
Origin: Eurasia
Poisoning: None