Mustard
Mustard, common name for a large family of pungent-juiced herbs, important for the many food plants and other crops it produces, and for its representative genus. The family contains about 390 genera and 3,000 species. It is cosmopolitan in distribution, with centers of diversity in the Mediterranean region and southwestern and Central Asia, where about two-thirds of the species occur. Most members of the mustard family are annual or perennial herbs; a few are shrubs or climbers. The flowers are characteristic and distinctive. Four petals are arranged opposite one another in the form of a cross. Six stamens are arranged in pairs. The filaments of the outer pair are short, whereas those of the two inner pairs are longer. The fruit is typically a capsule with two chambers divided by a false septum; at maturity, it splits in two from the bottom. Many variations on this basic fruit type are found in the family, and characteristics of the fruits are heavily used in distinguishing and cla