Rhamphospermum nigrum (syns. Mutarda nigra, Brassica nigra, and Sinapis nigra), black mustard, is an annual plant native to cooler regions of North Africa, temperate regions of Europe, and parts of Asia. It is cultivated for its dark-brown-to-black seeds, which are commonly used as a spice.
Description
Black mustard plants in Saarbrücken
Black mustard fruits at the Jardin des Plantes de Paris
Black mustard seeds
It is an upright plant, growing to 70 centimetres (28 in) in width and up to 1.2 metres (4 ft) tall in moist, fertile soil. The large stalked leaves are covered with hairs or bristles at the base, with smoother stems.
It blooms in summer (from May onwards in the UK). 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, beaked seed pods, which contain rounded seeds.
Despite their similar common names, black mustard and white mustard (genus Sinapis) are not in the same genus. Black mustard belongs to the same tribe as cabbage and turnips.
R. nigrum also resembles Hirschfeldia incana (hoary mustard, formerly known as Brassica geniculata), a perennial plant.
