Brassica
Brassica napus
cabbage, cole, mustard, turnip
canola, oilseed rape, rape, rapeseed, rutabaga, swede, swede rape, Swedish turnip, turnip, turnip mustard, winter rape
erect, unbranched or branched distally.
branched distally, 3–13 dm.
basal and cauline;
petiolate or sessile;
basal (persistent in B. tournefortii), rosulate or not, petiolate, blade margins entire, dentate, or lyrate-pinnatifid;
cauline petiolate or sessile, blade (base sometimes auriculate or amplexicaul), margins entire, dentate, lobed, or sinuate-serrate.
(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.
(middle and distal) sessile;
blade base auriculate or amplexicaul, (margins entire).
(corymbose), considerably elongated in fruit.
not paniculately branched, (buds overtopping or equal to open flowers).
sepals usually erect or ascending, rarely spreading, oblong [ovate], lateral pair usually saccate basally;
petals yellow to orange-yellow [rarely white], obovate, ovate, elliptic, or oblanceolate, claw often differentiated from blade, (sometimes attenuate basally, apex rounded or emarginate);
stamens tetradynamous;
filaments slender;
anthers oblong or ovate, (apex obtuse);
nectar glands confluent or not, median glands present.
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.
erect, spreading, ascending or divaricately-ascending, often slender.
spreading to ascending (slender), 1–3 cm.
siliques, dehiscent, sessile or stipitate, segments 2, linear, torulose or smooth, terete, 4-angled, or latiseptate; (terminal segment seedless or 1–3-seeded, usually filiform or conic, rarely cylindrical);
valves each prominently 1-veined, glabrous;
replum rounded;
septum complete;
ovules [4–]10–50 per ovary;
stigma entire or 2-lobed.
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.
uniseriate, plump, not winged, globose;
seed coat (reticulate or reticulate-alveolate), mucilaginous or not when wetted;
cotyledons conduplicate.
dark brown to black, light brown, or reddish, 1.8–2.7(–3) mm diam.;
seed coat finely reticulate-alveolate, not mucilaginous when wetted.
= 7, 8, 9, 10, 11.
= 38.
Brassica
Brassica napus
Species 35 (8 in the flora).
Crops of Brassica are the most important economic plants of the family. Probably, the earliest known utilization of mustards dates from Sanskrit records in India to 3000 b.c., but there is archaeological evidence suggesting that cultivation of cabbage in coastal northern Europe was occurring nearly 8000 years ago. Brassica crops include oilseeds, food crops (e.g., B. juncea, Asian vegetables; B. oleracea, cole crops; B. rapa, Chinese cabbages), fodder for animals, and condiments (B. juncea or B. nigra). The latter two species have also been used for medicinal purposes (I. A. Al-Shehbaz 1985). In addition to being noxious weeds, some species of Brassica are harmful or poisonous to humans and livestock (Al-Shehbaz).
Historically, native peoples of North America have used a number of “wild” Brassica species for both food and medicinal purposes (T. Arnason et al. 1981; H. A. Jacobson et al. 1988): Brassica species—young shoots cooked as greens by Iroquois and Malecite Indian tribes; B. nigra—seeds ground and used as snuff to cure head colds by the Meskwaki, and leaves used to relieve toothaches and headaches by the Mohegans; B. napus—bark used to treat colds, cough, grippe, and smallpox by the Micmac, and used for chilblains by the Rappahannock; B. oleracea—used for headaches by the Rappahannock; and B. rapa—used as medicine by the Bois Fort Chippewa.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
1. Cauline leaves sessile, blade bases auriculate and/or amplexicaul | → 2 |
1. Cauline leaves petiolate or sessile, blade bases tapered, not auriculate or amplexicaul | → 4 |
2. Biennials or perennials; petals (15-)18-25(-30) mm; terminal segments of fruits (3-)4-11 mm. | B. oleracea |
2. Annuals or biennials; petals 6-16 mm; terminal segments of fruits (5-)8-22 mm | → 3 |
3. Flowers usually not overtopping buds, rarely at same level, when open; petals pale yellow, 10-16 mm; terminal segments of fruits (5-)9-16 mm. | B. napus |
3. Flowers overtopping or equaling buds when open; petals deep yellow, 6-11(-13) mm; terminal segments of fruits 8-22 mm. | B. rapa |
4. Fruits and pedicels erect, ± appressed to rachises; fruits 10-25(-27) mm, not torulose; fruiting pedicels (2-)3-5(-6) mm. | B. nigra |
4. Fruits and pedicels spreading to ascending, not appressed to rachises; fruits often 2 cm+, torulose; fruiting pedicels (6-)8-20 mm | → 5 |
5. Fruits stipitate, gynophores 1.5-4(-5) mm, terminal segments 0.5-2.5(-3) mm; basal leaf blade margins entire or dentate. | B. elongata |
5. Fruits sessile or stipitate, gynophores to 1 mm, terminal segments (4-)5-20 mm; basal leaf blade margins lyrate to pinnatisect, or pinnatifid to pinnately lobed | → 6 |
6. Basal leaves persistent, blades with 4-10 lobes each side, surfaces hirsute; petals 4-7 × 1.5-2(-2.5) mm. | B. tournefortii |
6. Basal leaves deciduous, blades with 1-3 (or 4) lobes each side, surfaces glabrous or nearly so; petals (7-)9-13 × 3-7.5 mm | → 7 |
7. Fruits stipitate (gynophore 1-1.5 mm), 1.5-3 cm × 1.5-2 mm, terminal segment 3-6 mm. | B. fruticulosa |
7. Fruits sessile, (2-)3-5(-6) cm × 2-5 mm, terminal segment (4-)5-10 (-15) mm. | B. juncea |
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