Mullard: a semi-dry, non-fermented pickle made from pickled mustard stems. It is one of China’s famous specialties, and is also known as German sweet and sour cabbage and European pickled cucumbers. Three famous pickles in the world. Stem mustard: Brassica genus is an annual or biennial herb of the Brassicaceae family. China's famous specialty vegetables are rarely cultivated in European and American countries. Originated in Asia. The main lateral roots of mustard are distributed in a soil layer of about 30 cm, and the stems are shortened stems. The leaves are attached to the shortened stems and have shapes such as ellipse, oval, obovate, and lanceolate. The leaf color is green, dark green, light green, yellow-green, green to purple or purple-red. The leaf surface is smooth or wrinkled. The leaf margins are serrated or wavy, whole or have lobes of different shades and sizes. The corolla is cross-shaped, yellow, with four strong stamens, cross-pollination, but self-fertilization can also produce fruit. The seeds are round or oval, reddish brown or red in color.