1、 Petal difference

The petals of mud mustard are purple and some are red. They are fine filamentous, with a length of about 1 cm

The petals of shepherd's purse are usually white, open in the shape of a cross, obovate, and about 2.5mm in diameter

2、 Blade difference

The leaves of mud mustard are oblanceolate or oblong, with a length of about 7-21 cm. The apical fissure is triangular and has 7-8 opposite lobes

The leaf length of shepherd's purse is generally 12 cm, and the terminal lobes are very large, ovate to long ovate. There are 3-8 pairs of lobes, and the lobes are very small

3、 Height difference

Mud mustard can grow to about 100 cm. The stem is solitary, rarely clustered, and very thin. The upper part often has branches, and a few do not branch

The growth height of shepherd's purse is relatively low, usually half the height of the former. The stem is upright, with branches or single hair