Plectocephalus americanus (Nutt.) D. Don in Sweet, Brit. Fl. Gard., ser. 2: Ad t. 51. 1830
Plectocephalus americanus in Sweet, Brit. Fl. Gard., ser. 2: Ad t. 51. 1830
is new combination for Centaurea americana in J. Acad. Nat. Sci. Philadelphia 2: 117. 1821
Plectocephalus americanus in Sweet, Brit. Fl. Gard., ser. 2: Ad t. 51. 1830