Theodore Webster, USDA Agricultural Research Service, Bugwood.org

giant ragweed (Ambrosia trifida) plant(s)

Joseph M. DiTomaso, University of California - Davis, Bugwood.org

giant ragweed (Ambrosia trifida) seedling(s)

Bruce Ackley, The Ohio State University, Bugwood.org

giant ragweed (Ambrosia trifida) foliage

Theodore Webster, USDA Agricultural Research Service, Bugwood.org

mature plant

Bruce Ackley, The Ohio State University, Bugwood.org

giant ragweed (Ambrosia trifida) stem(s)

John D. Byrd, Mississippi State University, Bugwood.org

giant ragweed (Ambrosia trifida) plant(s)

Bruce Ackley, The Ohio State University, Bugwood.org

giant ragweed (Ambrosia trifida) seed(s)