Rapeseed (Brassica napus subsp. napus) is a bright-yellow flowering member of the family Brassicaceae (mustard or cabbage family), cultivated mainly for its oil-rich seed, which naturally contains appreciable amounts of toxic erucic acid. Canola are a group of rapeseed cultivars which were bred to have very low levels of erucic acid and are especially prized for use for human and animal food. Rapeseed is the third-largest source of vegetable oil and second-largest source of protein meal in the world.
Description & appearanceBrassica napus grows to 100 cm (39 in) in height with hairless, fleshy, pinnatifid and glaucous lower leaves which are stalked whereas the upper leaves have no petioles. Brassica napus can be distinguished from Brassica nigra by the upper leaves which do not clasp the stem, and from Brassica rapa by its smaller petals which are less than 13 mm (0.51 in) across.
Rapeseed flowers are yellow and about 17 mm (0.67 in) across. They are radial and consist of four petals in a typical cross-form, alternating with four sepals. They have indeterminate racemose flowering starting at the lowest bud and growing upward in the following days. The flowers have two lateral stamens with short filaments, and four median stamens with longer filaments whose anthers split away from the flower's center upon flowering.
The rapeseed pods are green and elongated siliquae during development that eventually ripen to brown. They grow on pedicels 1 to 3 cm long, and can range from 5 to 10 cm in length. Each pod has two compartments separated by an inner central wall within which a row of seeds develop. The seeds are round and have a diameter of 1.5 to 3mm. They have a reticulate surface texture, and are black and hard at maturity.