Plumbs are not mustard greens. According to the official website of the Botanical Society of China, mustard is an annual herbaceous plant of the genus Brassica in the Brassicaceae family. The plant is up to 150 centimeters tall. The young stems and leaves have thorns. Meicai is a type of prune, made from the stems and leaves of mustard. Therefore, plum vegetables and mustard greens are two different ingredients, so plum vegetables are not mustard greens. Meicai is a common Hakka delicacy. It is mainly produced in Meizhou and Huizhou areas. According to legend, it was a vegetable sent by Mei Xiangu, so it is called Meicai. It is a characteristic traditional dish in Guangdong (Meizhou and Huizhou) and belongs to the pickled category. As a food product, plum vegetables are also known as rich and noble vegetables. With a cultivation history of more than a thousand years, plum vegetables have been listed as palace tributes by successive dynasties and are called "Huizhou tribute vegetables".