Flora of North America species comparison

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Brassica napus

canola, oilseed rape, rape, rapeseed, rutabaga, swede, swede rape, Swedish turnip, turnip, turnip mustard, winter rape
Habit Annuals or biennials; (taproot slender or swollen); (glaucous), glabrous, glabrescent, or pubescent, (trichomes coarse).
Stems

branched distally, 3–13 dm.
Basal leaves

(rosulate when biennial);

petiole (often winged), to 15 cm;

blade lyrate-pinnatifid, ± pinnately lobed, 5–25(–40) cm × 20–70(–100) mm, lobes 0–6 each side, (smaller than terminal), surfaces (glaucous), glabrous or sparsely hairy when immature, glabrescent, or, rarely, pubescent.
Cauline leaves

(middle and distal) sessile;

blade base auriculate or amplexicaul, (margins entire).
Racemes

not paniculately branched, (buds overtopping or equal to open flowers).
Flowers

sepals (5–)6–10 × 1.5–2.5 mm;

petals golden or creamy to pale yellow, broadly obovate, 10–16 × (5–)6–9(–10) mm, claw 5–9 mm, apex rounded;

filaments (5–)7–10 mm;

anthers 1.5–2.5 mm.
Fruiting pedicels

spreading to ascending (slender), 1–3 cm.
Fruits

spreading to ascending, smooth or slightly torulose, terete, (3.5–)5–10(–11) cm × (2.5–)3.5–5 mm;

valvular segment with 12–20(–30) seeds per locule, (3–)4–8.5(–9.5) cm, terminal segment usually seedless, rarely 1 or 2-seeded (attenuate-conic, thin), (5–)9–16 mm.
Seeds

dark brown to black, light brown, or reddish, 1.8–2.7(–3) mm diam.;

seed coat finely reticulate-alveolate, not mucilaginous when wetted.
2n

= 38.

Brassica napus
Phenology Flowering May–Sep.
Habitat Roadsides, disturbed areas, waste places, cultivated and abandoned fields, escape from cultivation
Elevation 0-500 m (0-1600 ft)
Distribution
from FNA
AK; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KY; LA; MA; MD; ME; MI; MO; MS; NC; NH; NJ; NY; OH; OK; OR; PA; TN; UT; VA; VT; WA; WI; WV; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; Europe; Asia; Africa [Introduced in North America; introduced also in Mexico, Central America, South America, Atlantic Islands, Australia]
[WildflowerSearch map]
[BONAP county map]
Discussion

Brassica napus is both a crop and a sporadically occurring naturalized weed in North America, grown in two forms recognized by some as subspecies. Subspecies napus (rape, rapeseed, or canola) is an annual with slender roots widely cultivated as an oil crop and is the most commonly naturalized. Subspecies rapifera Metzger [= subsp. napobrassica (Linnaeus) Hanelt] (rutabaga, swede, or Swedish turnip) is a biennial with fleshy roots that rarely escapes from cultivation.

Although Brassica napus has been reported as a weed from most southeastern states, it is very likely that most reports represent misidentifications of B. rapa (I. A. Al-Shehbaz 1985). It is difficult to distinguish between plants of B. napus and B. rapa that lack flowers and proximal leaves.

Brassica napus is an allotetraploid derived from hybridization between the B. oleracea complex (n = 9) and B. rapa (n = 10). Its center of origin is uncertain but likely Mediterranean Europe, with molecular data supporting evidence of multiple independent origins between the parental taxa B. oleracea and B. rapa and its related n = 9 species (Song K. et al. 1993). Specimens from West Virginia have not been observed.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 7, p. 422.
Parent taxa Brassicaceae > tribe Brassiceae > Brassica
Sibling taxa
B. elongata, B. fruticulosa, B. juncea, B. nigra, B. oleracea, B. rapa, B. tournefortii
Synonyms B. napobrassica, B. napus var. oleifera, B. oleracea var. napobrassica
Name authority Linnaeus: Sp. Pl. 2: 666. (1753)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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