This annual diploid (2n = 18) of crop fields ("charlock") is widespread across North America, but herbarium records are thin (PL). It is probably undercollected (Y) due to misguided botanical boredom with brassicaceous weeds. The cultivated S. alba L. ("white mustard") is also widespread but even less often recorded (PL), and should be expected in Ky. (2n = 24).