Chickweed

Stellaria media (L.) Vill.

Family: Caryophyllaceae.

Names:

Chickweed.

Summary:

A delicate annual herb, with small, paired, egg shaped, pointed-tip leaves on long, round, weak stems that have a line of hairs between the nodes. It has small white flowers with 5 deeply notched petals that are shorter than the sepals.

Description:

Cotyledons:

Two. Oval with a pointed tip, 14-20 mm long. Base tapered. The petiole is 5-10 mm long and almost vertical and the blade is at right angles and almost horizontal. Hairless or few on the petiole and base of the blade. The seedling has a long hypocotyl and an epicotyl.

First Leaves:

Arise in pairs, opposite, 5-10 mm long, oval with a pointed tip and 5-10 mm long petiole. A few fine hairs on the petiole and base of leaf.

Leaves:

Does not form a rosette. Opposite, paired. Upper leaves may have a few fine hairs.
Stipules - None, but the paired leaves are united by a short sheath.
Petiole - Almost as long as the blade and joined to the petiole of the opposite leaf by a short sheath. Petiole shorter or absent towards the ends of branches.
Blade - Egg shaped, soft, thin, 6-25 mm long x 4-14 mm wide, tip pointed, midrib groove, smooth edges. Often sparse hairs on the edges or the base and on the blades of the upper leaves. Upper leaves are often broader than the stalked lower leaves.

Stems:

Initially erect becoming prostrate and sometimes mat forming and sprawling, 100-400 mm long, slender, angular to round, weak, sometimes hollow. Usually a single line of white multicellular, curved hairs, swapping sides at the nodes, and in line with leaf axils. Occasionally glandular hairy or hairless. Branched from the base and along length. After flowering the stems often curve downwards.

Flower head:

Few to many flowers on stalks (pedicels) at the ends of slender stems or in leaf axils forming terminal leafy cymes. Pedicels slender, erect or curved, hairy.

Flowers:

White with nectaries.
Ovary - 1 celled. 3 styles.
Sepals - 5, narrowly egg shaped, 4-6 mm long, obtuse tip. Outer ones leafy and usually with curved multicellular hairs. Inner ones often with membranous edges. Sparsely hairy
Petals - 5, white, 2-6 mm long, deeply divided, shorter than the sepals. Sometime absent.
Stamens - Usually 3-10.
Anthers - Purple, circular in outline.

Fruit:

Globular to egg shaped capsule, 5-6 mm long, slightly longer than the sepals, with several seeds. May have hairs.

Seeds:

Very small, 1-1.5 mm diameter, red-brown, granular with rounded warts, flattened, circular to kidney shaped in outline.

Roots:

Taproot.

Key Characters:

Annuals to 250 mm tall.
Leaves broadly ovate, no stipules, lower ones petiolate.
Stems with a line of hairs up one side of each internode.
Styles 3, free, 4-5 mm long.
Sepals 5, free or almost so, obtuse, usually with one central nerve, rarely 3 nerved.
Petals 5, deeply 2 lobed, shorter than sepals, sometimes absent.
Capsule globular to ovoid, opening to the base in 6 valves.
Seeds several.
Adapted from J.M. Black, N.T. Burbidge and J.R. Wheeler.

Biology:

Life cycle:

Annual. Germinates anytime often with a main germination from autumn to spring. Flowers late-winter/spring.

Physiology:

Reproduction:

By seed.

Flowering times:

Late winter to spring in western NSW.
July to December in SA.
July to September in Perth.
Winter to spring in WA.

Seed Biology and Germination:

Vegetative Propagules:

None.

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Spread by seed.

Origin and History:

Europe. Almost cosmopolitan.

Distribution:

ACT, NSW, NT, QLD, SA, TAS, VIC, WA.
Occurs in all parts of Tasmania.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate. Mediterranean.

Soil:

Sands and many other soil types.

Plant Associations:

Significance:

Beneficial:

Used as a green salad or cooked vegetable.

Detrimental:

Weed of crops, gardens, vegetables, horticulture, river flats, roadsides, urban bushland, pasture and disturbed areas.
A competitive weed in higher rainfall areas.

Toxicity:

Not recorded as toxic.

Legislation:

None.

Management and Control:

Thresholds:

Eradication strategies:

Prevent seed set.
Plant competitive pastures.
Graze.

Herbicide resistance:

Biological Control:

Related plants:

Lesser Chickweed (Stellaria pallida) is similar but has no petals, is smaller and yellowish green.
Swamp Starwort (Stellaria angustifolia, Stellaria palustris).

Plants of similar appearance:

Australian Crassula, Dense Crassula, Spreading Crassula (Crassula spp.)
Four-leaved Allseed (Polycarpon tetraphyllum)
Mouse-eared Chickweed (Cerastium holosteoides) is similar as a seedling but has much shorter petioles and it has hairs all over both surfaces of the leaf.
Pearlwort (Sagina apetala)
Petty Spurge (Euphorbia peplus) doesn't have a line of hairs down the stem and exudes a white sap when damaged.
Pigweed (Portulaca spp.)
Pimpernel (Anagallis arvensis) is similar but it has a short merging petiole on the cotyledon, the cotyledon is not almost at right angles to its petiole and it has no petioles on its lower leaves.
Sticky Mouse-eared Chickweeds (Cerastium spp.)
Waterblinks (Montia fontana) is very similar as a seedling but it is completely hairless, does not have a midrib groove, has broader cotyledons, a thicker leaf blade and a broader petiole.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P146-147. Photo.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P355. Diagram.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P64.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P306-307. Photo.

Gilbey, D. (1989). Identification of weeds in cereal and legume crops. Bulletin 4107. (Western Australian Department of Agriculture , Perth). P18-19. Photos.

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). P132-133. Photo.

Hyde-Wyatt, B.H. and Morris, D.I. (1975). Tasmanian weed handbook. (Tasmanian Department of Agriculture, Hobart, Tasmania). P78-79. 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). #1164.2.

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). P110.

Wilding, J.L. et al. (1987). Crop weeds. (Inkata Press, Melbourne). P92. Photos. Diagrams.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.