Squarrose knapweed Centaurea virgata Lam.

Asteraceae — (Sunflower family)

A long-lived taprooted perennial typically reaching heights of 12 to 18 inches. Stems are highly branched, with deeply dissected lower leaves and bract-like upper leaves. Flower heads are relatively small, containing 4 to 8 rose or pink colored flowers, usually develoing no more than 3 or 4 seeds per head. Bract tips are recurved or spreading, with the terminal spine longer than lateral spines on each bract. It is often confused with diffuse knapweed, but differs principally in the fact that it is a true perennial, and bracts are recurved. Unlike diffuse knapweed, seed heads are highly deciduous, falling off the stems soon after seeds mature.

Squarrose knapweed is a competitive rangeland weed native to the eastern Mediterranean area. It is not yet widely distributed in the West, but has gained footholds in Utah, California and Oregon.
(Courtesy of Weeds of the West)