An erect, hairy, annual herb, to 40 cm tall with finely lobed leaves and purple-veined, yellow flowers in winter that produce a tadpole shaped pod about 6 mm long.
Description:
Cotyledons:
Two. Heart shaped. Tip indented. Sides convex. Base tapered. Hairless blade. Petiole longer than the blade and hairy. Folded together in the seed.
First leaves:
Deeply lobed. Tip pointed. Very hairy.
Leaves:
Alternate.
Stipules -
Petiole - Yes.
Blade - Deeply lobed and the lobes are lobed into parallel sided, rounded segments. Short bristly hairs. Tip pointed to rounded. Base tapered to squarish.
Stems:
Erect. Short bristly hairs. Up to 400 mm tall. Branching from base.
Flower head:
Alternate at ends of branches. Long bracteate raceme.
Flowers:
Yellow with purple veins.
Bracts -
Ovary - 6 ovules,
Style - Leafy, as broad and long as the pod.
Sepals - Erect, 4 mm long.
Petals - 4, entire, clawed, 8-9 mm long
Stamens - Free.
Anthers -
Fruit:
Tadpole shaped, beaked pod, 4-7 mm long, with bristly hairs on the veins. On 2-3 mm curved stalks. 2 celled. Valves are concave with 3 hairy nerves. The beak is flattened and 3-4 mm long. Releases seed on maturity.
Seeds:
3-4 in each cell, flattened spherical to tear shaped, 1-1.5 mm diameter, dark brown. Surface smooth, shiny, hairless and minutely dimpled.
Roots:
Taproot.
Key Characters:
Biology:
Life cycle:
Annual. Germinates autumn/winter, grows rapidly, flowers in spring and seeds freely.
Physiology:
Reproduction:
By seed.
Flowering times:
June to July in SA.
Mainly spring in NSW.
Seed Biology and Germination:
Vegetative Propagules:
None.
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
More prevalent in years of good winter to spring rainfall.
Origin and History:
Southern Europe, Mediterranean, western Asia.
Distribution:
ACT, NSW, NT, QLD, SA, VIC, WA.
Habitats:
Climate:
Semi arid areas. Less common in temperate areas.
Soil:
Red earth sandplains, rocky hillsides, skeletal soils.
Plant Associations:
Brown Gibber, Mulga, Bella rosewood, bladder saltbush, black bluebush.
Significance:
Beneficial:
Does not host Root Lesion Nematode (Pratylenchus thornei)
Detrimental:
Weed of crops, pastures, railways and roadsides.
Unpalatable.
Spreading rapidly.
Poor host of Root Lesion Nematodes (Pratylenchus neglectus) and allows some build up of numbers.
Toxicity:
Not recorded as toxic.
Legislation:
None.
Management and Control:
Thresholds:
Eradication strategies:
Control new infestations because this weed is rapidly spreading.
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:
Biological Control:
Related plants:
None.
The native Brassicaceae species usually have short, broad and smooth pods.
Plants of similar appearance:
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P133. Diagram.
Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P380.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P321. Photo.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #259.1.