Brassica rapa is a plant species growing in various widely cultivated forms including the turnip (a root vegetable); napa cabbage, bomdong, bok choy, and rapini; and Brassica rapa subsp. oleifera, an oilseed which has many common names, including turnip rape, field mustard, bird rape, and keblock.
The oil made from the seed is sometimes also called canola or colza.
Cultivated in Europe for over 4000 years, probably native to central and southern Europe, now spread throughout world, including most parts of the tropics.
Brassica rapa @ Purdue Horticulture Brassica rapa @ Cornell Gardening