Mustard is not a plant, but is made from ground mustard seeds or leaves.

Mustard, also known as wasabi, western yam cabbage, and mustard powder, is generally divided into two types: green mustard and yellow mustard. Yellow mustard originated in China, is the mustard seeds ground into; green mustard (green mustard spicy) originated in Europe, with horseradish (horse radish) manufacturing, add coloring was green, its spicy smell stronger than yellow mustard, and has a unique aroma.

History of Mustard:

Brown mustard is native to China and has a long history. It has been consumed at court since the Zhou Dynasty and has been used as a natural herb since ancient times before being introduced to Japan. It was developed in Japan because it is an island country and there are many people who eat seafood.

Today wasabi is one of the most important flavorings in Japanese cuisine, and it is especially used in sashimi and sushi. Wasabi is usually made by grinding the roots of the wasabi plant. Freshly grated wasabi has a light green color, a sticky consistency, and a fresh, pungent odor.

Western mustard and Japanese mustard look like two completely different plants, but the chemical composition of their pungent flavors is identical. Western mustard is on average 1.5 times more pungent than Japanese mustard.

Reference: Baidu Encyclopedia - Mustard