Annual Ragweed, Bur Ragweed, Common Ragweed, Flat Spine Bur-ragweed: Ambrosia artemisiifolia (Synonym: Franseria acanthicarpa) -
Beach-bur, Cutleaf Beach Bur, Cutleaf Beach Bur, Silver Beachweed, Silver Bur Ragweed: Ambrosia chamissonis var. bipinnatisecta (Synonyms: Franseria chamissonis ssp. bipinnatisecta, Franseria chamissonis var. bipinnatisecta) -
Beach Bur, Silver Beachweed: Ambrosia chamissonis var. chamissonis (Synonyms: Franseria chamissonis ssp. chamissonis, Franseria chamissonis var. chamissonis)
Cuman Ragweed, Perennial Ragweed, Western Ragweed: Ambrosia psilostachya (Synonyms: Ambrosia psilostachya var. californica, Ambrosia psilostachya var. coronopifolia, Ambrosia psilostachya var. lindheimeriana, Ambrosia rugelii) -
Giant Ragweed, Great Ragweed: Ambrosia trifida (Synonyms: Ambrosia aptera, Ambrosia trifida var. integrifolia, Ambrosia trifida var. texana, Ambrosia trifida var. trifida) -