Mouse-eared Chickweed

Cerastium fontanum Baumg.

Synonyms - Cerastium holosteoides, Cerastium triviale, Cerastium fontanum, Cerastium fontanum ssp. vulgare, Cerastium fontanum ssp. triviale, Cerastium vulgatum.

Family: Caryophyllaceae.

Names:

Cerastium is from the Greek word kerastes meaning horned and refers to the shape of the capsule.
Mouse-ear Chickweed refers to the mouse ear shape of the leaves.

Summary:

A hairy, hollow stemmed annual herb with loose clusters of white flowers with 5 lobed petals. It has opposite leaves that look like mouse ears.

Description:

Cotyledons:

Two. The cotyledon is 4 to 6 mm long overall. Tip pointed. Sides convex. Base tapered. Surface hairless. Petiole shorter than blade and hairless or has a few hairs at the base. The seedling has a short hypocotyl and a short epicotyl.

First leaves:

Paired, dark green, 5 to 10 mm long overall with a short petiole. Some long hairs are present on the upper surface

Leaves:

Paired, dark green.
The plant does not develop as a rosette.
Short leafy shoots present in some axils.
Petiole - Short or none on upper leaves
Blade - Elliptical or oblong, 10-25 mm long x 5-10 mm wide. Obtuse tip. Simple hairs on the upper and lower surface and occasionally a few glandular hairs.
Stem leaves - The lower stem leaves are shortly petiolate, but the upper stem leaves, which are 15 to 30 mm long, are sessile or have an ill defined merging petiole. The leaves carry simple hairs on the upper and lower surface and occasionally a few glandular hairs.

Stems:

Often erect initially but usually become prostrate and spreading as the plant increases in size. Vertical stems reach some 250 mm long and spreading stems twice that. Stems are branched at the base, circular in cross section, hollow, and have simple and occasionally some glandular hairs.

Flower head:

Rather loose cluster. At the ends of stems.

Flowers:

5 to 10 mm in diameter.
Ovary -
Sepals - 4-5 mm long. Edges and tip membranous.
Petals - 5 white petals that are deeply divided into two lobes. Shorter than sepals.
Stamens -
Anthers -

Fruit:

Capsule, 8-12 mm long.

Seeds:

Brown, tiny, 0.4-0.8 mm diameter, ridged, warty.

Roots:

Key Characters:

Hairs near tip of sepals do not project beyond the tip.
Round hollow stems.
5 petalled, white flowers.

Biology:

Life cycle:

Germination occurs in autumn and spring.
Annual. Cerastium fontanum is perennial and this name is occasionally misapplied to this plant.

Physiology:

Reproduction:

By seed.

Flowering times:

Spring.

Seed Biology and Germination:

Vegetative Propagules:

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Origin and History:

Europe. Cosmopolitan.

Distribution:

ACT, NSW, QLD, TAS, VIC.
Common in both the Northern and Southern parts of Tasmania.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate.

Soil:

Plant Associations:

Significance:

Beneficial:

Detrimental:

Weed of crops, cultivation, lawns and disturbed areas.

Toxicity:

None reported.

Legislation:

None.

Management and Control:

Thresholds:

Usually of minor importance in broad acre crops.

Eradication strategies:

Herbicide resistance:

Biological Control:

Related plants:

Balearic Mouse eared Chickweed (C. balearicum)
Curtis' Mouse-eared Chickweed (C. pumilum)
Levantine Mouse-eared Chickweed (C. comatum)
Little Mouse eared Chickweed. (C. semidecandrum)
Sea Mouse-eared Chickweed (C. diffusum)
Sticky Mouse-eared Chickweed (C. glomeratum)

Plants of similar appearance:

Mouse-ear Chickweed is extremely difficult to distinguish from Sticky Mouse-ear Chickweed in the seedling stage. The mature plant has a dark green colour while Sticky Mouse-ear is decidedly yellowish. The upper leaves of Mouse-ear Chickweed are much longer and taper towards the base, while the inflorescence is much more open. The complete or relative absence of glandular hairs is not a diagnostic feature as these may also be absent from Sticky Mouse-ear Chickweed.
The Mouse-ear Chickweeds are, in the seedling stage, superficially similar to Chickweed and Montia. The presence of hairs on the leaves separates the Mouse- ear Chickweeds from these other species. Chickweed has a long thin petiole. The leaves of Montia are thick, stiff and fleshy. Mouse-ear Chickweed can also be confused with French Catchfly if the distinctive flowers of the latter are absent. The leaves of Catchfly are much longer in relation to their width and have their widest point closer to the tip; the upper stem leaves in particular are long and narrow, and the leaf pairs are more widely separated along the stem.
Cerastium glomeratum, C. viscosum are very similar to C. holosteoides.
Australian Crassula, Dense Crassula, Spreading Crassula (Crassula spp.)
Chickweed (Stellaria media)
Four-leaved Allseed (Polycarpon tetraphyllum)
Pearlwort (Sagina apetala)
Pimpernel (Anagallis arvensis)
Waterblinks (Montia spp.)
Pigweed (Portulaca spp.)

References:

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P164.

Hyde-Wyatt, B.H. and Morris, D.I. (1975). Tasmanian weed handbook. (Tasmanian Department of Agriculture, Hobart, Tasmania). P76-77. Diagram.

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). #285.6.

Acknowledgments:

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