A light green, low lying annual plant with much divided, carrot like leaves up to 100 mm long, in a dense rosette with sharp, prickly seeds. It does not have stoloniferous stems.
Description:
Cotyledons:
Two.
Leaves:
Form a dense, tufted rosette.
Petiole - Broad papery base that clasps the stem.
Blade - Much divided into parallel sided segments like a carrot leaf, up to 100 mm long. Long soft hairs especially at the base.
Stems:
Low lying. No stolon like branches.
Flower head:
Green, no stalk, clustered in the middle of the rosette, globular, up to 10 mm round with egg shaped, green, silky bracts.
Flowers:
Bracts - Egg shaped, green, silky.
Ovary - Conical receptacle.
'Petals' - None.
Stamens -
Anthers -
Fruit:
3mm long, wedge shaped achene with a sharp, rigid spine on top and crosswise wrinkles near the base.
Seeds:
Enclosed in the fruit.
Roots:
Fibrous.
Key Characters:
Small herb.
No stoloniferous stems.
No milky latex.
Heads sessile, heterogamous-discoid, distinct, female flowers in several to many rows with no ligule, disk flowers few, 4 toothed.
Receptacle naked.
No corolla on female flowers.
Involucre bracts pubescent, herbaceous or thin in 2 sub equal rows, not spine tipped.
Achenes flattened, winged with a persistent hardened style, no pappus.
From J.M. Black and N.S. Lander.
Biology:
Life cycle:
Annual. Flowers in spring.
Physiology:
Reproduction:
By seed.
Flowering times:
Spring in western NSW.
Seed Biology and Germination:
Vegetative Propagules:
None.
Hybrids:
Allelopathy:
Population Dynamics and Dispersal:
Spread by seed.
Origin and History:
South America.
Distribution:
NSW, QLD, SA, VIC.
Habitats:
Climate:
Temperate. Mediterranean.
Soil:
Plant Associations:
Significance:
Beneficial:
Detrimental:
Weed of roadsides, lawns and recreational areas.
Toxicity:
Not recorded as toxic.
Legislation:
None.
Management and Control:
Hormone herbicides provide good control if applied in winter before flowering. Bromoxynil provides good control up to seed set.
Thresholds:
Eradication strategies:
Spray with Bromoxynil plus MCPA in August and November each year.
Small areas can be treated with 1 litre of Tordon 75-D in 250 litres of water in June to provide residual control for the season.
Herbicide resistance:
Biological Control:
Related plants:
Jo-jo (Soliva pterosperma) forms harder spines and has running stoloniferous stems.
Soliva stolonifera has globular flower heads, stoloniferous stems and occurs in NSW and VIC.
Plants of similar appearance:
Cotula, Carrot Weed.
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P116. Photo.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P669.
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). #1144.1.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.