RUSSIAN KNAPWEED, Centaurea
repens L. 1, stem and leaves; 2, new shoots; 3,
seeds; 4, root. Perennial, reproducing by seeds and rhizomes.
Roots deep and extensive with new shoots coming from various depths.
Stems 2 to 3 feet (60 to 90 cm) tall, very hairy, ridged, tough,
and woody, branches numerous, tipped with flower heads. Leaves hairy;
lower ones deeply indented, resembling those of dandelions; upper leaves
short, narrow, and smooth-edged. Flower heads about 1 inch
(2.5 cm) in diameter, composed of disk flowers only, which vary from white
to light rose or light blue; each head surrounded by small, leafy bracts
with smooth tips. Seed grayish or yellowish, smooth, about 1/8 inch
(3 mm) long. Found in waste places or dry-land areas. Persists in
cultivated fields when established.