Brassica napus L.

Brassica species are annual, biennial, perennial rarely undershrubs, glaucous or sparsely hirsute. Rootstock slender or tuberous. Stem erect or ascending, simple or branched. Basal radical leaves in rosulate or not, oblong to oblanceolate, pinnatifid or pinnatisect, base amplexicaul, margin dentate or entire, glabrous or pubescent, apex obtuse, petiolate or sessile, cauline leaves sagittate or auriculate, base attenuate or cuneate, margin dentate or rarely entire, apex acute, petiole subsessile or sessile. Inflorescence raceme corymbs, axillary or terminal, many flowered, elongated in fruit, ebracteate. Flowers bisexual, yellow rarely white or pink, actinomorphic, pedicel slender, sepals 4, erect, oblong or ovate, glabrous or pubescent, basal pair saccate or not, petals 4, spathulate-obovate, margin entire, apex obtuse, almost twice long as than sepals, clawed, almost equal or slightly longer than sepals. Stamens 6, tetradynamous, filaments not dilated at the base, anthers oblong-ovate, nectar glands 4, lateral and median, ovary superior, bicarpellary, syncarpous, linear, ovules 4-48, style distinct, stigma capitate or bilobed. Fruit siliqua, dehiscent, linear oblong, erect or slightly curved, compressed, valves papery, prominent midveined, torulose or smooth, glabrous or rarely pubescent, style short or obsolete. Seeds few to many, uniseriate, rarely biseriate, not winged, globose-ovoid, minutely reticulate, mucilaginous or not when soaked, cotyledons conduplicate.

Brassica species flowers are complete, bisexual, i.e., with functional male (androecium) and female (gynoecium), including stamens, carpels and ovary. Pollination is entomophilous i.e., by insects, or cleistogamy i.e., by self or allogamy i.e., by cross pollination. Flowering/Fruiting: March-August.

Seeds may be dispersed by autochory i.e., self dispersal, anemochory i.e., wind dispersal, zoochory i.e., dispersal by birds or animals, anthropochory i.e., dispersal by humans.

Erect annual or biennial herbs, about 40-150 cm tall. Rootstock slender, stout, tuberous and fusiform. Stem sparsely branched, glabrous, sometimes sparely pubescent near the base. Basal cauline leaves alternate, broadly obovate to oblanceolate in outline, lyrately-pinnatifid or not, about 6-28 x 2-18 cm across, base cuneate, margin shallow dentate or undulate, apex obtuse or rounded, lateral lobes 2-6 on either side of the midrib, terminal lobes the largest, glabrous or sparsely pubescent, petiolate about 3-15 cm long, middle leaves oblong-ovate, upper cauline leaves linear-lanceolate or narrow oblong-oblanceolate, about 2-8.5 x 0.7-2.5 cm across, base shallow cordate or cuneate, margin entire or rarely shallow dentate, petiole sessile. Inflorescence racemes, axillary or terminal, 20-100+ flowered, elongated in fruit, about 5-50 cm long ebracteate. Flowers bisexual, bright yellow, actinomorphic, pedicels erect, divaricate, slender, about 1-2.5 cm long, sepals 4, oblong, ascending, about 5-10 x 1.5-2.5 mm across, petals 4, spathulate-obovate, base attenuate or caudate, margin entire, apex obtuse or rounded, about 3-16 x 5-10 mm across, claw about 5-8 mm across. Stamens 6, tetradynamous, filaments about 4-10 mm long, anthers oblong, about 1.5-2.5 mm long, nectar glands 4, lateral and median, ovary superior, bicarpellary, syncarpous, linear, ovules 4-40, style obsolete, stigma capitate. Fruit siliqua, dehiscent, linear, erect or slightly curved, compressed, valves papery, prominent midveined, about 3-8 cm long, torulose or smooth, glabrous or rarely pubescent, terminal segment conical, with one seed or not. Seeds 10-30, uniseriate, not winged, dark brown or blackish, globose-ovoid, about 1.5-2.5 mm across, minutely reticulate, mucilaginous when soaked, cotyledons conduplicate.

Brassica species are susceptible to insect pests, virus, mildews and rusts.

Cultivated fields of subtropical and temperate places.

Not evaluated (IUCN).

Cultivated for seed oil.