This is an annual weed , reproducing by seed. Napus leaves are dark green, smooth, hairless, and sessile. Rapa leaves are lighter green, clasping, and hairy on the underside and petiole.
Flowers are pale yellow, small, and appear on a raceme.
The inflorescence of rapa appears more rounded than napus because flowers extend past the tip of the raceme. Napus flowers do not extend past the tip resulting in a more flattened appearance. Flowering occurs two weeks later in napus. Napus has fewer but larger pods which shatter easily. The pods of rapa are shorter and more resistant to shattering.