According to R. J. Moore (1972), reports of Centaurea nervosa Willdenow [C. uniflora Turra subsp. nervosa (Willdenow) Bonnier & Layens] from New York were based on a specimen referable to C. phrygia subsp. phrygia. Moore called these plants C. austriaca Willdenow, which J. Dostál (1976) treated as a synonym of C. phrygia subsp. phrygia.