Description: Annual, biennial or perennial herbs, glaucous, glabrous or with scattered simple hairs. Lower leaves usually lyrate-pinnatisect, petiolate; upper leaves reducing.
Inflorescence paniculate or corymbose, flowers usually yellow.
Siliqua terete to somewhat flattened, commonly partly contracted between seeds, valves usually with 1 prominent vein; beak mostly seedless (rarely 1- or 2-seeded); seeds numerous in valve region, 1 row per loculus.
Distribution and occurrence: World: c. 100 species, Europe, Mediterranean & Asia. Australia: 9 species (several varieties introduced & naturalized), all States.
Many species are cultivated for food. Brassica oleracea L. is widely cultivated and many selected forms are recognized as varieties: var. capitata (Cabbage), var. gemmifera (Brussels Sprouts), var. botrytis (Cauliflower), var. italica (Broccoli). Other useful species of Brassica include B. rapa (Turnip, Wild Turnip), B. napus (Swede, Coleseed and Rape), B. fimbriata (Kale), B. nigra (Black Mustard) and B. chinensis (Chinese Cabbage).
Text by L. Retter & G. J. Harden
Taxon concept:
Taxa not yet included in identification key
Brassica x napus
| | Key to the species | |
| 1 | Upper stem leaves sessile and more or less bract-like or upper part of stem leafless | 2 |
| Upper stem leaves petiolate or narrowed to base | 3 |
| 2 | At least basal leaves hairy, stem leaves at least half stem-clasping | Brassica rapa |
| All leaves glabrous, glaucous, stem leaves less than a third stem-clasping
Back to 1 | Brassica oleracea |
| 3 | Ovary on a gynophore | Brassica fruticulosa |
| Ovary sessile
Back to 1 | 4 |
| 4 | Fruit spreading on pedicel 7–20 mm long; beak more than 4 mm long | 5 |
| Fruit appressed on pedicel 2–5 mm long; beak less than 4 mm long
Back to 3 | Brassica nigra |
| 5 | Basal leaves lyrate-pinnatisect with 1 or 2 pairs of lobes, sparsely bristly; beak 4–10 mm long, narrower than stigma | Brassica x juncea |
| Basal leaves runcinate-pinnatisect with 6–10 pairs of lobes, densely bristly; beak 8–20 mm long, as broad as the stigma
Back to 4 | Brassica tournefortii |
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