It is an upright plant, with large stalked leaves. They are covered with hairs or bristles at the base, but on the stem smoother. It can reach up to tall or even up to in moist fertile soil. It blooms in summer, from May onwards. The flowers have four yellow petals, which are twice as long as the sepals. Each stem has around four flowers at the top, forming a ring around the stem. Later, the plant forms long seed pods, that contain four rounded seeds.
Taxonomy
It was formally described by Karl Koch in "Deutschl. Fl." ed.3 on page 713 in 1833. This was based on a description by the Swedish botanist Carl Linnaeus. The Latin specific epithetnigra is derived from the Latin word for black. This is due to the black seeds.
Distribution and habitat
It is native to tropical regions of North Africa, temperate regions of Europe and parts of Asia.
More than 2,000 years ago, the plant was used as a condiment, it was mentioned by the Roman author Columella in the 1st century A.D. The plant leaves were also pickled in vinegar. In 13th century France the seeds were ground and used. They were mixed with partially fermented grape juice to create "mout-ardent". This became later "moutarde", now called mustard in English. A spice is generally made from ground seeds of the plant, with the seed coats removed. The small seeds are hard and vary in color from dark brown to black. They are flavorful, although they have almost no aroma. The seeds are commonly used in Indian cuisine, for example in curry, where it is known as rai. The seeds are usually thrown into hot oil or ghee, after which they pop, releasing a characteristic nutty flavor. The seeds have a significant amount of fatty oil, mainly oleic acid. This oil is used often as cooking oil in India, it is called "sarson ka tel". In Ethiopia, where it is cultivated as a vegetable in Gondar, Harar and Shewa, the shoots and leaves are consumed cooked and the seeds used as a spice. Its Amharic name is senafitch. Black mustard is thought to be the seed mentioned by Jesus in the Parable of the Mustard Seed. Since the 1950s, black mustard has become less popular as compared to brown mustard, because some cultivars of brown mustard have seeds that can be mechanically harvested in a more efficient manner.
Folk medicine
In the UK, the plant was used to make "hot mustard baths", which would aid people with colds. Ground seeds of the plant mixed with honey are widely used in eastern Europe as cough suppressant. In Eastern Canada, the use of mouche de moutarde to treat respiratory infections was popular before the advent of modern medicine. It consisted in mixing ground mustard seeds with flour and water, and creating a cataplasm with the paste. This cataplasm was put on the chest or the back and left until the person felt a stinging sensation. Mustard poultice could also be used to aid muscular pains.
Similar plants
Despite their similar common names, black mustard and white mustard are not closely related. Black mustard belongs to the same genus as cabbage and turnips. B. nigra also resembles Hirschfeldia incana, or hoary mustard,, which is a perennial plant.
