Centaurea stoebe; spotted knapweed [Asteraceae]  An introduced 1-4’ tall perennial or biennial herb of dry disturbed sites.  Stiff, wiry stems bear sparse grey-green alternate, pinnately lobed leaves.  Upper stems terminate in attractive 1” wide pink to purple flower heads subtended by distinctive black-tipped bracts.  Flowers mid-summer into fall.  Foliage and roots exude toxins that can kill neighboring plants.  Native to Eastern Europe, but aggressively invasive in our area.  [131]