Herbs or shrubs, mostly herbaceous. Often scented with compounds called mustard oils. Leaves alternate, estipulate, simple to bipinnate.
Flowers perfect, regular.
Sepals 4, distinct. Petals 4, distinct. Mustard is prepared from the ground seeds of Brassica nigra, B. juncea and Sinapsis alba. Mustards are also important as oil crops. Rapeseed oil, prepared from Brassica napus , has numerous industrial uses.