Rapeseed and Swede
- Subspecies, varieties and synonyms: Rape, Oilseed Rape, Rapa, Rappi, Cole, Canola (B. napus var. oleifera, B. napus ssp. oleifera), Swedish Turnip, Swede, Yellow Turnip, Rutabaga (B. napus var. rapifera, B. napus var. napobrassica, B. napus ssp. rapifera)
- Family: Mustard Family – Brassicaceae (Cruciferae)
- Growing form: Annual or biennial herb. Root thin (var. oleifera), conical, thick, yellow–green–violet (var. napobrassica).
- Height: 100–150 cm (40–60 in.). Stem branched, glabrous.
- Flower: Corolla regular (actinomorphic), yellow, approx. 1–1.5 cm (0.28–0.6 in.) across; petals four, 10–15 mm (0.4–0.6 in.) long. Sepals 4. Stamens 6, of which 4 long and 2 short. Gynoecium fused, a single carpel. Inflorescence an elongating raceme in fruiting stage. Flowers fairly level with buds.
- Leaves: Alternate, lowest stalked, upper stalkless, amplexicaul. Blade glabrous, bluish green, basal leaves shallow-lobed, upper leaves entire, lanceolate.
- Fruit: Many-seeded, opens lengthwise, usually 5–8 cm (2–3.2 in.) long, spreading–quite erect siliqua, terminated by a terete, 1–2 cm (0.4–0.8 in.) long, seedless beak.
- Habitat: Fields, roadsides, rubbish tips, harbours and loading areas. Cultivated, left over from old gardens and an escape.
- Flowering time: June–July.
The ancestor of rapeseed and swede is not known to grow ferally. It is believed to have originated relatively late in Europe, probably as a cross between wild cabbage (B. oleracea) and turnip mustard (B. rapa; see wild turnip), but it is unclear if swede was a prototype of rapeseed, or vice versa.
According to the way that it is used, rapeseed is an autumn or spring annual that is cultivated for its oil in temperate climates around the world. Finland constitutes rapeseed’s northern limit, and seeds that sprout in the autumn do not overwinter as well as turnip rape (Brassica rapa ssp. oleifera; also known as biennial turnip rape, canola, winter turnip rape): rapeseed’s delicate terminal bud sits slightly proud of the earth, but turnip rape’s is better protected, sitting snugly against the earth. On the other hand, spring rapeseed that is sown in the spring ripens so late in the autumn that the harvest cannot be guaranteed, unlike spring turnip rape. Rapeseed is grown for fodder rather than oil further north, and swede grows well even further up north.
Swede (also known as Swedish turnip, rutabaga or yellow turnip) is a biennial root vegetable that has been cultivated from 1600th century. Swede and rapeseed sometimes grow wild in Finland as escapes or aliens, most often close to cultivated land or in areas with lively traffic. It is also possible to find closely related turnip rape, whose lowest leaves are bright green and slightly hairy. It also has a slightly smaller flower and its buds open up underneath its flowers.