HABIT	A PERENNIAL HERB SPREADING RAPIDLY BY HORIZONTAL ROOTS WHICH GIVE RISE TO AERIAL SHOOTS.
STEMS	30-150 CM TALL, SLENDER, GREEN, FREELY BRANCHED.
LEAVES	ALTERNATE, THE BASE SESSILE AND CLASPING OR SHORTLY DECURRENT; LEAVES GENERALLY OBLONG IN OUTLINE, MARGIN VARIABLE FROM ENTIRE TO DEEPLY PINNATELY SEGMENTED, SPINY.
FLOWERS	PLANTS DIOECIOUS, ALL HEADS OF A PLANT EITHER MALE OR FEMALE. MALE HEADS GLOBULAR, SOMEWHAT SMALLER THAN THE FLASK-SHAPED FEMALE HEADS. FLORETS ALL TUBULAR, ROSE-PURPLE TO PINKISH, LESS COMMONLY WHITE. FLORETS OF FEMALE HEADS 23-26 MM LONG; FLORETS OF MALE HEADS 12-14 MM LONG.
FRUITS	ACHENES 2.5-4 X 1 MM, STRAIGHT OR SLIGHTLY CURVED, STRAW OR LIGHT-BROWN. PAPPUS COPIOUS, WHITE, FEATHERY, 20-30 MM LONG ON MATURE ACHENES.