Corn Mustard - Sinapis arvensis
Other Names:
Charlock, Wild Mustard,
Brassica kaber
Stems 10–50 cm. Leaves 5–14 cm long, undivided to pinnate with dentate margins. Vestiture sparse, simple hairs below, glabrous above. Petals 8–12 mm long. Fruit erect, 2–3 cm long, nearly glabrous, the beak 7–16 mm long (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).