An erect, lobed leaf, almost hairless annual mustard, 50-100 cm tall with pale yellow, 4 petal flowers and long squarish seed pods. The stem leaves have short petioles to distinguish it from similar Radish, Mustard and Turnips.
Description:
Cotyledons:
Two. Heart shaped. Sides convex. Tip indented. Base tapered to squarish. Hairless. Petiole longer than the blade.
First leaves:
Oval, edges toothed and lobed. Hairy on upper and lower surface. Scattered hairs on the petiole.
Leaves:
Alternate, and don't form a definite rosette.
Stipules - None
Petiole - Hairy. As long or shorter than the blade on lower leaves and short on the upper leaves.
Blade - Blue green with a whitish bloom. Up to 100 mm long by 60 mm wide. Lower ones have one or two pairs of irregular lobes and al larger oval terminal lobe and are sparsely hairy usually with simple, short, stiff hairs.. Upper ones have no lobes and are hairless. Tip pointed. Base squarish to tapered.
Stem leaves - Shortly petiolate, not lobed and smaller than lower leaves and tend to turn upwards. Tip pointed. Base squarish to tapered. Surface hairless.
Stems:
Erect with rather erect branches and somewhat blue green. Up to 1000 mm tall. Hairless.
Flower head:
Branched and at the top of the stem. Flat to convex corymb that elongates with age.
Flowers:
Yellow on slender spreading stalks (pedicels).
Ovary - Superior. sessile, 2 celled, cylindrical.
Stigma - Head like.
Sepals - 4 in 2 rings. Green, 4-5 mm long. Somewhat spreading. Sometimes with a few tiny hairs near the tip.
Petals - 4 in a single ring, alternate to sepals. Yellow, egg shaped, 7-9 mm long. Don't overlap.
Stamens - Yellow. 6 with 4 inner ones and 2 shorter side ones.
Anthers - Yellow. 2 celled.
Fruit:
Long pods up to 20-60 mm long by 2-4 mm wide with a beak up to 4-10 mm long. Square to slightly 4 angled in cross section. Constricted between the seed. Prominent veins on valves. Seeds attached to a thin membrane that divides the 2 compartments in the pod. Beak is 2-12 mm long or about a third the length of the pod and usually seedless, slender and tapering or conical with the tip narrower than the stigma on the end. 8-16 seeds per pod. Pod is somewhat erect, or upward bending, 8-17 mm long stalks.
Valves with a conspicuous mid vein and domed and swollen over the enclosed seed.
Cross walls (septa) is thin and indented from the seeds
Seeds:
Yellow to dull brown to black, globular, 1-2 mm diameter with a conspicuous black attachment scar (hilum). Surface hairless. Surface network (reticulum) is obvious with fine, smooth, sharp-edged lines surrounding the shallow, flat, pitted interspaces. (Other species of Mustard tend to have concave interspaces). Radicle is difficult to see.
Lutea variety has yellow seeds.
Roots:
Taproot.
Key Characters:
Cotyledons conduplicate
Leaves not succulent.
Lower leaves sparsely hairy or glabrous and not forming a definite rosette
Upper leaves shortly petiolate
Stems sparsely hairy or glabrous
Hairs simple.
Ovary sessile or subsessile at the summit of the pedicel
Inflorescence elongating from a convex corymb
Petals pale yellow, not twisted, not long acuminate and less than twice as long as the sepals
Fruit a siliqua, at least 3 times longer than wide, longitudinally dehiscent, often angular or somewhat compressed with a strong central mid vein and faint side veins.
Fruit sessile or subsessile at the summit of the pedicel
Fruit beak narrower at the apex than at the stigma. Beak 4-12 mm long and about a third the length of the pod.
Seeds in 1 row per cell. Reticulate seeds have a flat and not concave interspace.
Adapted from John Black and B.L. Rye
Biology:
Life cycle:
Annual. Seeds germinate from autumn to spring. Grows during the cooler months, flowers in spring and dies off in summer.
Physiology:
Drought tolerant (Hewson, 1976)
Reproduction:
By seed.
Flowering times:
August to September in WA or spring.
Spring in Western NSW.
Summer in Victoria.
Seed Biology and Germination:
Vegetative Propagules:
None.
Hybrids:
Possibly hybrid in origin.
Allelopathy:
Population Dynamics and Dispersal:
Spread by seed
Origin and History:
Native to Southern and Eastern Asia.
Distribution:
ACT, NSW, NT, QLD, SA, VIC, WA.
Europe.
Habitats:
Climate:
Temperate.
Soil:
Plant Associations:
Significance:
Beneficial:
Food, fodder, oils, medicinal.
Used as a green manure crop in Asia.
Grown as an oilseed crop occasionally in Australia.
Grown for oil and medicinal uses in the southern USSR.
Detrimental:
Weed of crops and disturbed areas.
Toxicity:
Possibly toxic.
Symptoms:
Treatment:
Remove stock from infestations if ill thrift observed.
Legislation:
None.
Management and Control:
Ploughing normally provides effective control by killing plants and burying seeds too deep for establishment.
Hormone herbicides and sulfonylureas are also effective.
Thresholds:
Probably similar to Wild Turnip with more than 10 plants/m2 worth spraying in cereals. In Canola, Indian Mustard has the potential to contaminate the seed and very high levels of control should be practiced.
Eradication strategies:
Prevent seed set for at least 5 years.
Deep plough the area if possible in autumn. Keep subsequent workings shallower to avoid bringing up buried seed.
Spray large plants with a mixture of 10 g/ha Eclipse® plus 250 mL/ha Brodal® plus 1% spray oil.
Spray new seedlings plus a 5 m buffer area until just wet with a mixture of 10 mL Brodal® in 10 L water.
Remove isolated plants by hand before flowering for several years.
In bushland areas a mixture of 0.5 g of Eclipse® plus 25 mL of wetting agent in 10 L water and sprayed onto the weed until just wet usually provides good control with little damage to native species.
Herbicide resistance:
None reported, but it is expected to become tolerant to sulfonylurea herbicides after multiple applications.
Biological Control:
A range of endemic diseases and insects attack it which is probably the reason for its relatively low levels in Australia.
Related plants:
Black Mustard (Brassica nigra)
Broccoli (Brassica oleracea var. italica)
Brussels Sprouts (Brassica oleracea var. gemmifera)
Cabbage (Brassica oleracea var. capitata)
Cauliflower (Brassica oleracea var. botrytis)
Chinese Cabbage (Brassica chinensis)
Indian Mustard (Brassica juncea)
Kale (Brassica oleracea var. acephala)
Kohlrabi (Brassica oleracea var. gongylodes)
Mediterranean Turnip (Brassica tournefortii) is very similar but lower leaves that are bristly, bordered with hairs, a smaller terminal lobe and 5-10 pairs of basal-pointing side lobes. The beak of the pod is usually longer at 8-12 mm and is the same width as the stigma at its tip.
Rape or Canola (Brassica napus var. napus)
Rapeseed (Brassica rapa var. sylvestris)
Savoy cabbage (Brassica oleracea var. sabauda)
Smooth Stemmed Turnip (Brassica oxyrrhina)
Swede (Brassica napus var. napobrassica)
Turnip (Brassica rapa var. rapa)
Twiggy Turnip (Brassica fruticulosa)
Winter Rape (Brassica napus var.biennis)
Brassica barelieri ssp. oxyrrhina
Brassica elongata
The native Brassicaceae species usually have short, broad and smooth pods.
Plants of similar appearance:
Wild Radish, Turnips and Mustards.
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P130.
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). 377.
Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P318. Photo.
Felfoldi, E.M. (1993). Identifying the Weeds Around You. (Department of Agriculture Victoria). P140-142.
Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).
Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume . P. Diagram.
Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P113.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #149.5.
Marchant et al (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P161.
Moerkerk, M.R. and Barnett, A.G. (1998). More Crop Weeds. R.G. and F.J. Richardson, Melbourne. P63. Diagrams. Photos.
Randall, J.M. and Marinelli, J. (1996) Invasive Plants. (Brooklyn Botanic Gardens Inc. Brooklyn). P. Photo.
Acknowledgments:
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