Among the many varieties of mustard, four are particularly widespread. Wild mustard or field mustard (Sinapis Arvensis L.) is considered a very resistant weed, while white mustard (Sinapis alba L.) has a blond bark whose seeds are grown for silage and as green manure. Black mustard (Brassica nigra K.) was long used for making condiments and mustard poultices, but its yield is too low today. Finally, brown mustard (Brassica Juncea) visible here saw its use spread at the beginning of the 20th century and is now the main component of the condiment.