Sherardia arvensis L.
Family: Rubiaceae or Aizoaceae.
Sherardia commemorates the English botanist William Sherard (1659-1728).
Arvensis is from the Latin arvum meaning cultivated field and refers to the plants association with cultivation.
Summary:An annual, mat forming herb with rings of 4-6 narrow pointed leaves with tiny forward pointing spines on the upper surface and edges. It has clusters of 4-8, small, 4 petalled, purple to pink or white flowers from September to December surrounded by 8 floral leaves at the ends of the branches. The stems are hollow and square with downward pointing, tiny spines on the corners, The mature plant is erect in habit when small but as it grows it becomes semi-erect and spreading or mat forming, with the ends of the branches erect.
Two. 6-9 mm long, round to club shaped, sessile or with only a very short merging petiole. Tip indented. Edges smooth. Base squarish to tapered. Surface smooth, dull, somewhat frosted. Hairless. The seedling has a long hypocotyl and a long epicotyl.
First Leaves:Arise in whorls, the first whorls have 4 leaves and later whorls 4-6 leaves. The first leaves are oval, 3 to 5 mm long and stalkless, with short hairs on the top and margin and a few on the underside that are mostly on the veins,. Tip pointed. Edges with forward pointing bristles. Base tapered.
Leaves:Arise in whorls of 5 to 6 on stems. Does not form a basal rosette.
Stipules - Identical to leaves.
Petiole - None.
Blade - Egg to spear shaped, 4 to 15 mm long x 1.5 to 4 mm wide, acute tip with a sharp point where the midrib extends beyond the leaf tip. Short, stout, forward pointing hairs on the upper surface and margin, and a few hairs on the lower surface mostly confined to the veins. Edges stiff and look like veins.
Stem leaves - Upper leaves are narrower than lower leaves.
Stems: Initially erect and becoming low lying, weak and mat forming with the ends of stems bending upwards with age, much branched from the base, 200-400 mm long, hollow, cruciform or square with ridged corners in cross section. Downward pointing (retrorse, scabrid) hairs.
Flower head:Small, 4-10 flowers with no stalks in tight clusters at the ends of branches, surrounded by eight to ten floral leaves that are joined at the base.
Flowers: Funnel shaped, 2-3 mm wide with 4 spreading pink to lilac or white petals. Bisexual.
Calyx - Tiny, 6 toothed.
Petals - Pink to lilac or white, funnel shaped, 3-5 mm long x 3-5 mm diameter, tube longer than the 4 spreading petals.
Fruit:Dry, oblong, 2-5 mm long, doesn't release seed, with 2 nut like fruitlets that are stuck together with a persistent, toothed calyx on top. Fruit crowded in the surrounding floral leaves.
Seeds:Black, enclosed in the fruit, egg shaped, 1 mm long x 0.75 mm wide. Tip flat to pointed with 3 spikes. Surface grooved, ridged and covered in short pale hairs that are denser towards the base. Base pointed.
Leaves usually appearing whorled owing to leaf like stipules.
Hollow, square stem.
Flowers in involucre of leafy bracts united at the base.
Calyx 6 toothed.
Corolla funnel shaped.
Ovules solitary in each cell.
Fruit dry, of 2 small nut like fruitlets.
Adapted from J.M. Black, N.T. Burbidge and James and Allen.
Annual. Seeds germinate mainly in the autumn with some in spring.
Flowering times:September to November in WA.
September to December in SA.
September to December in NSW.
Seed Biology and Germination:Vegetative Propagules:
Population Dynamics and Dispersal:
Spread by seed, which is carried by animals, water and wind or in contaminated grains and produce.
Origin and History:Europe. North western Asia.
Introduced to WA in 1996 as a contaminant of Canola seed from New Zealand.
Distribution:ACT, NSW, NT, SA, TAS, VIC, WA.
In all parts of Tasmania but is less common in the South than the North. It occurs in Europe, the Middle East, North and South Africa, North and South America and New Zealand.
Climate analysis indicates the southern agricultural areas of both eastern and western Australia and Tasmania have climates suitable for the establishment of Field Madder (Randall pers. com.).
Courtesy Australia's Virtual Herbarium.
Soil:Most abundant on nitrogen rich, loamy, alkaline soils.
Plant Associations:Tuart. Peppermint (Agonis spp.).
Significance:It is principally a weed of waste areas and gardens but occurs occasionally in crops. It is not of great economic significance in Australia. It is considered a weed in 12 countries, but is not a principal weed in any of these (Holm et al, 1979).
Weed of cereals, clover seed crops, gardens, horticultural crops, roadsides, olives, ryegrass seed crops, strawberries, Tuart and Peppermint woodlands and disturbed areas.
Competes for space and nitrogen.
Toxicity:Not recorded as toxic.
Legislation:Management and Control:
A number of selective herbicides are available for use in various crops.
Prevent seed set.
Spray with 1 litre of Tordon® 75-D in 100 litres of water in winter.
Herbicide resistance:It has developed resistance to simazine in olive groves. (Saavedra and Pastor, 1990).
Biological Control:Related plants:
Plants of similar appearance:Field Madder is similar in general appearance to Cleavers (Galium aparine) and Three-horned Bedstraw (Galium tricornutum) but much smaller. It is distinguished from Cleavers in the seedling stage by the difference in cotyledon shape and, in the mature plant, by the difference in the flower colour, no corolla tube and by the leaves which are much smaller, more distinctly pointed, and fewer in the whorls. Field Madder has hairs on the edge of the leaf that point forward whereas Cleavers and Three-horned Bedstraw have hairs on the edges of the leaves that point backwards (away from the leaf tip).
Bedstraw (Galium spp.) has no corolla tube.
References:Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P798. Diagram.
Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P339-341. Diagram.
Harden, Gwen J. (1991) Flora of NSW. Volume 4. Page Diagram.
Holm, R.J., Pancho, J.V., Herberger, J.P. and Plunckett, D.L. (1979). A geographical atlas of world weeds. John Wiley and Sons, New York.
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). P212-213. Photo.
Hyde-Wyatt, B.H. and Morris, D.I. (1975). Tasmanian weed handbook. (Tasmanian Department of Agriculture, Hobart, Tasmania). P60-61. Diagrams.
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). #1130.1.
Moerkerk, M.R. and Barnett, A.G. (1998). More Crop Weeds. R.G. and F.J. Richardson, Melbourne. P116. Diagrams. Photos.
Saavedra, M. and Pastor, M. (1990). New herbicidal treatments on non-tilled olive groves. Acta Horticulturae. No. 286, 303-306; International symposium on olive growing, Cordoba, Spain, 26-29 Sept. 1989.
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