White mustard (Sinapis alba), also called yellow mustard, is an annual plant of the cabbage family. It is sometimes also referred to as Brassica alba or B. hirta. It is native to the Mediterranean region, Europe and Asia Tropical, but is now widespread worldwide. Grown for its seeds, it is used to make the condiment mustard, as a fodder crop, or as a green manure.
White mustard is an annual, growing to 70 centimetres (28 in) high with stalkless pinnate leaves, similar to Sinapis arvensis. The yellow flowers of S. alba contain 4 petals per flower and 4 alternating sepals. In addition, their pods are approximately 2.0–4.2 cm long.
Sinapis alba is a long day plant, which means they flower when the amount of light received exceeds their critical photoperiod. Pollen from S. alba is able to be dispersed through wind and insect pollinators, such as wild bees, bumblebees, and flower flies. Additionally, white mustard is an obligate outcrossing species, that is, white mustard is self-incompatible and cannot self-fertilize.
