Diffuse Knapweed (Centaurea diffusa Lam.)

DIFFUSE KNAPWEED

(Centaurea diffusa Lam.)

GROWTH HABIT:  Annual or biennial, bushy, up to 2 ft. tall.  Rosette formed first year, flowering stalk elongates second year.

LEAVES:  Greyish-green, alternate, basal leaves whorled, upper leaves much reduced.  Covered with fine hair.

STEMS:  Hairy, erect, single main stem from a rootstock, branched near or above the base.

FLOWERS:  Solitary, usually white, sometimes pink, rose or lavender; seedhead bracts end as sharp, rigid spines.

ROOTS:  Elongated taproot.

SEEDS:  Oblong, dark brown or grey with longitudinal lines.

OTHER:  May seriously reduce productive potential of infested rangelands.