Carduus acantholepis (Hemsl.) Greene accepted as Cirsium acantholepis (Hemsl.) Petr. (original description)
Carduus americanus (A.Gray) Greene accepted as Cirsium scariosum (Poir.) Nutt. (original description)
Carduus amplifolius (Greene) Greene (original description)
Carduus andersonii (A.Gray) Greene accepted as Cirsium andersonii (A.Gray) Petr. (original description)
Carduus arizonicus (A.Gray) Greene accepted as Cirsium arizonicum (A.Gray) Petr. (original description)
Carduus bernardinus Greene accepted as Cirsium occidentale var. californicum (A.Gray) D.J.Keil & C.E.Turner (original description)
Carduus breweri (A.Gray) Greene accepted as Cirsium douglasii var. breweri (A.Gray) D.J.Keil & C.E.Turner (original description)
Carduus californicus (A.Gray) Greene accepted as Cirsium occidentale var. californicum (A.Gray) D.J.Keil & C.E.Turner (original description)
Carduus callilepis Greene accepted as Cirsium remotifolium var. odontolepis Petr. (original description)
Carduus candidissimus Greene accepted as Cirsium occidentale var. candidissimum (Greene) J.F.Macbr. (original description)
Carduus crassicaulis Greene accepted as Cirsium crassicaule (Greene) Jeps. (original description)
Carduus edulis (Nutt.) Greene accepted as Cirsium edule Nutt. (original description)
Carduus excelsior (B.L.Rob.) Greene accepted as Cirsium excelsius (B.L.Rob.) Petr. (original description)
Carduus fontinalis (Greene) Greene accepted as Cirsium fontinale (Greene) Jeps. (original description)
Carduus grahamii (A.Gray) Greene accepted as Cirsium grahamii A.Gray (original description)
Carduus heterolepis (A.Gray) Greene accepted as Cirsium subcoriaceum (Less.) Sch.Bip. ex Sch.Bip. (original description)
Carduus hydrophilus Greene accepted as Cirsium hydrophilum (Greene) Jeps. (original description)
Carduus linearifolius Greene accepted as Cirsium linearifolium (original description)
Carduus mexicanus (DC.) Greene accepted as Cirsium mexicanum DC. (original description)
Carduus mohavensis Greene accepted as Cirsium mohavense (Greene) Petr. (original description)
Carduus neomexicanus (A.Gray) Greene accepted as Cirsium neomexicanum A.Gray (original description)
Carduus ochrocentrus (A.Gray) Greene accepted as Cirsium ochrocentrum subsp. ochrocentrum A.Gray (original description)
Carduus parryi (A.Gray) Greene accepted as Cirsium parryi (A.Gray) Petr. (original description)
Carduus potosinus Greene accepted as Cirsium potosinum (original description)
Carduus pringlei (S.Watson) Greene accepted as Cirsium pringlei (S.Watson) Petr. (original description)
Carduus quercetorum (A.Gray) Greene accepted as Cirsium quercetorum (A.Gray) Jeps. (original description)
Carduus raphilepis Greene accepted as Cirsium rhaphilepis (Hemsl.) Petr. (original description)
Carduus rothrockii (A.Gray) Greene accepted as Cirsium arizonicum var. rothrockii (A.Gray) D.J.Keil (original description)
Carduus rusbyi Greene accepted as Cirsium mohavense (Greene) Petr. (original description)
Carduus scopulorum Greene accepted as Cirsium eatonii var. eriocephalum (A.Gray) D.J.Keil (original description)
Carduus undulatus var. douglasii (DC.) Greene accepted as Cirsium douglasii DC. (original description)
Carduus undulatus var. megacephalus (A.Gray) Greene accepted as Cirsium undulatum var. undulatum (Nutt.) Spreng. (original description)
Carduus undulatus var. nevadensis Greene accepted as Cirsium inamoenum (Greene) D.J.Keil (original description)
Carduus velatus (S.Watson) Greene accepted as Cirsium velatum (S.Watson) Petr. (original description)
Carduus venustus Greene accepted as Cirsium occidentale var. venustum (Greene) Jeps. (original description)