• Carduus Linnaeus, 1753
• Carduus acanthoides Linnaeus
• Carduus altissimus Linnaeus accepted as Cirsium altissimum (L.) Hill
• Carduus americanus (Gray) Rydb. accepted as Cirsium tioganum (Congd.) Petrak
• Carduus araneosus Osterhout accepted as Cirsium araneans Rydb.
• Carduus arvensis (L.) Robson accepted as Cirsium arvense (L.) Scop.
• Carduus austrinus Small accepted as Cirsium texanum Buckl.
• Carduus carolinianus Walt. accepted as Cirsium carolinianum (Walt.) Fern. & Schub.
• Carduus coloradensis Rydb. accepted as Cirsium tioganum (Congd.) Petrak
• Carduus crispus Linnaeus
• Carduus discolor (Muhl. ex Willd.) Nutt. accepted as Cirsium discolor (Muhl. ex Willd.) Spreng.
• Carduus helleri Small accepted as Cirsium undulatum (Nutt.) Spreng.
• Carduus inamoenus Greene accepted as Cirsium neomexicanum Gray
• Carduus lanceolatus Linnaeus accepted as Cirsium vulgare (Savi) Ten.
• Carduus lecontei (Torr. & Gray) Pollard accepted as Cirsium lecontei Torr. & Gray
• Carduus macounii Greene accepted as Cirsium edule Nutt.
• Carduus macrocephalus Desf. accepted as Carduus nutans Linnaeus
• Carduus macrolepis Peterm. accepted as Carduus nutans Linnaeus
• Carduus marianus Linnaeus accepted as Silybum marianum (L.) Gaertn.
• Carduus muticus (Michx.) Pers. accepted as Cirsium muticum Michx.
• Carduus nevadensis Greene accepted as Cirsium humboldtense Rydb.
• Carduus nutans Linnaeus
• Carduus nuttallii (DC.) Pollard accepted as Cirsium nuttallii DC.
• Carduus orthocephalus Wallr.
• Carduus pinetorum Small accepted as Cirsium horridulum Michx.
• Carduus pulchellus Greene accepted as Cirsium calcareum (M.E. Jones) Woot. & Standl.
• Carduus pumilus Nutt. accepted as Cirsium pumilum (Nutt.) Spreng.
• Carduus pycnocephalus Linnaeus
• Carduus repandus (Michx.) Pers. accepted as Cirsium repandum Michx.
• Carduus smallii (Britt.) Ahles accepted as Cirsium horridulum Michx.
• Carduus spathulatus Osterhout accepted as Cirsium scapanolepis Petrak
• Carduus spinosissimus Walt. accepted as Cirsium horridulum Michx.
• Carduus tenuiflorus W. Curtis
• Carduus thoermeri Weinm.
• Carduus tracyi Rydb. accepted as Cirsium undulatum (Nutt.) Spreng.
• Carduus truncatus Greene accepted as Cirsium calcareum (M.E. Jones) Woot. & Standl.
• Carduus undulatus Nutt. accepted as Cirsium undulatum (Nutt.) Spreng.
• Carduus virginianus Linnaeus accepted as Cirsium virginianum (L.) Michx.
• Carduus vulgaris Savi accepted as Cirsium vulgare (Savi) Ten.