Indian mustard (Brassica juncea) is a cool-season annual herb that belongs to the Cruciferae (Brassicaceae) plant family. It has erect patent branches, green, petioled lower leaves. It produces bright yellow flowers which turn into sickle-shaped green seed pods. B. juncea is considered an invasive plant in the United States.
B. juncea is known for its ability to accumulate high amounts of metals from the soil from where its grown. If B. juncea is grown on soils with high selenium, lead, arsenic, and other metals that are toxic in high amounts, and it is ingested by horses, it can have toxic consequences to the animal.