GIANT RAGWEED
AMBROSIA TRIFIDA  COMPOSITAE (SUNFLOWER)

ALSO CALLED: WILD HEMP, GREAT RAGWEED, HORSEWEED, BITTERWEED, AND KINGHEAD

A FIELD GUIDE TO THE PLANTS OF ARIZONA  #809  P. 256

NEWCOMB'S WILDFLOWER GUIDE  PP. 438-439

COMMMON WEEDS OF THE UNITED STATES PP. 368-369

WILDLY SUCCESSFUL PLANTS  PP. 116-117