Chinese Mustard: Brassica juncea
Canola, Rapeseed, Rutabaga: Brassica napus
Black Mustard: Brassica nigra - Stem leaves petiolate, not clasping. The blades are lobed, with the terminal lobe larges and one to several pairs of narrow, lateral lobes. The upper leaves are toothed rather than lobed. The siliques are erect, measuring 1-2.5 cm long and 1-1.5 mm wide.
Common Mustard, Field Mustard: Brassica rapa (Synonym: Brassica campestris) - Stem leaves have heart-shaped, clasping bases. The siliques are spreading to ascending, measuring from 3-7 cm long and 2.5-3.5 mm wide. The beak (upper portion) of the silique is 4-sided.
Charlock, Wild Mustard: Sinapis arvensis (Synonyms: Brassica kaber, Brassica kaber var. pinnatifida) - The lower stem leaves are obovate in shape with toothed margins and petioles. The beak (upper portion) of the silique is somewhat flattened.