An erect, branching annual, with a persistent rosette of stalked leaves and almost leafless stems usually less than 1 m tall and are prickly hairy near the base. The leaves are lobed and bristly especially on the underside. The side lobes point backwards toward the base of the leaf and are smaller than the terminal lobe. The stem leaves are smaller. It has yellow fading to white, 4 petalled flowers with 6 stamens in spring. The petals are 5-8 mm long.
The seed pods that are slender, smooth, 30-70 mm long and almost cylindrical that splits on maturity to release about 16 globular seeds about 1 mm in diameter. The narrower tip (beak) lacks seeds. Seed pods remain entire and do not break into smaller pieces.
Native to Europe and Asia it has become a common weeds of roadsides and disturbed areas near cultivation rarely invades bush.
It is commonly referred to as Wild Turnip.
Description:
Cotyledons:
Two. Heart shaped. Tip indented. Sides convex. Base squarish. Hairless. Petiole longer than blade.
First leaves:
Oval. Stiff hairs. Tip round. Edges lobed.
Leaves:
Form a rosette that persists late into the season. The leaves have a turnip like odour when crushed.
Petiole - Short on basal leaves. None on stem leaves.
Blade - Deeply lobed. 20-200 x 5-50mm (up to 400 x 140mm). 5-10 pairs of lobes that are often bluntly toothed. Large terminal lobe. The ends of the side lobes point toward the base of the leaf. Dense stiff hairs on the underside especially along the midrib. Warts with hairs on upper surface.
Stem leaves - Few apart from some small bracts near branch junctions. Lance shaped and usually not lobed or toothed. Few hairs.
Stems:
Erect. Up to 1800 mm, but usually around 600 mm. Elongates in winter/spring. Much branched from the base and even more so along the length of the stem. Round. Often with purplish tinge. Stiff hairs at the base, hairless near top.
Flower head:
In flat topped clusters (racemes) with a few flowers near the end of the stems.
Flowers:
Yellow fading to white, may be with a bit of violet at the base.
Ovary -
Sepals - 2-4 mm long.
Petals - 4 petals, 5-8 mm long.
Stamens -
Anthers -
Fruit:
Narrow, cylindrical pod on a 8-15 mm stalk. No conspicuous midrib. Usually 40-55 x 2-3 mm (up to 75 mm). Convex on both sides. 2 rows of spherical seeds separated by a papery wall. Splits open lengthwise. Slender, conical beak is 0-2 seeded, 8-30 mm long. Barely constricted between the seeds. 12-20 seeds per pod.
Seeds:
Reddish brown. Spherical. 1-2 mm diameter. Surface smooth, dimpled and hairless.
Roots:
Long taproot.
Key Characters:
No conspicuous midrib on pod.
Bristly leaves.
Pale yellow flowers.
Very few leaves on the much branched stem.
Biology:
Life cycle:
Annual. Germinates autumn/winter. Flowers in July-October mainly.
Reproduction:
Flowering times:
Winter to spring.
Seed Biology and Germination:
Has dormant seed.
Vegetative Propagules:
None
Hybrids:
Forms hybrids.
Allelopathy:
Probably.
Ecology, Population Dynamics and Dispersal:
Spread by seed.
Branched stems break at the base and tumble in the wind or catch on animals to distribute seed.
Origin and History:
Mediterranean.
Distribution:
ACT, NSW, NT, QLD, SA, VIC, WA.
Habitats:
Crops, cultivated areas, roadsides, sheep yards, wastelands and disturbed areas.
Climate:
Temperate.
Soil:
Prefers sandy soils.
Plant Associations:
Mallee and Mulga.
Significance:
Beneficial:
Stabilises disturbed areas.
Does not host Root Lesion Nematode (Pratylenchus thornei)
Detrimental:
Weed of crops causing yield reductions due to competition and contamination of the grain sample.
Rarely eaten in quantity by stock.
May taint milk.
Tangles in harvesting machinery.
Branched stem tumbles in the wind and collects on fence lines trapping sand.
Poor host of Root Lesion Nematode (Pratylenchus neglectus) and allows some build up of numbers.
Toxicity:
Contains goitre producing substances.
Symptoms:
Goitre.
Treatment:
Remove stock from infested area.
Legislation:
None.
Management and Control:
Thresholds:
1 plant/m2 can cause grain contamination.
5-20 plants/m2 cause around 10% yield loss in cereals.
Eradication strategies:
Prevent seed set for 10 years.
Most of the Brassicaceae weeds have dormant seeds that continue to germinate throughout the season and for several years. They often mature and set seed very quickly. Manual removal is effective but must be done at least every 8-10 weeks. Once pods are formed, seed will often mature even if the plant has been uprooted. Soil disturbance often leads to a flush of seedlings.
Many are somewhat unpalatable, so grazing only offers partial control. They often flourish in undergrazed, sunny areas.
In bushland situations, fairly selective control can be achieved with 100 mL spray oil plus 0.1 g Eclipse® or 0.5 g Logran® in 10 L water. 5 mL Brodal® is often added to this mix to provide residual control of seedlings. Spray the plants until just wet from the seedling stage up to pod formation.
Isolated plants should be removed manually and burnt if flowering or seeding and a 10 m buffer area sprayed with 10 mL Brodal® in 10 L water.
500 mL/ha of glyphosate(450g/L) can be used at flowering to reduce the seed set of most species on roadsides without causing significant damage to most native plants.
Wick application with 1 part glyphosate(450g/L) in 2 parts water or overall spraying with 100 mL glyphosate(450g/L) in 10 L water provides reasonable control of most species though Wild Radish tends to regrow.
Herbicide resistance:
None reported.
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)
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 elongata
The native Brassicaceae species usually have short, broad and smooth pods.
Plants of similar appearance:
Smooth stemmed Turnip (Brassica barrelieri ssp. oxyrrhina) (found in WA) has more sharply serrated leaf lobes, purple veins in the petals, a beak with about half the length of the pod, more constriction between the seeds and a more prominent midrib on the pod.
Wild radish.
Indian hedge mustard.
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P130-131. Diagram.
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P377.
Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). p213.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P319-320. Photo.
Gilbey, D. (1989). Identification of weeds in cereal and legume crops. Bulletin 4107. (Western Australian Department of Agriculture , Perth). p64. Photos. Diagram.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne). p.
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #195.21.
Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). p162.
Meadly, G.R.W. (1965). Weeds of Western Australia. (Department of Agriculture - Western Australia). p81. Diagram.