Looking-glass Bush

Coprosma repens A.Rich.

Synonyms -

Family: Rubiaceae

Names:

Coprosma is from the Greek kopros meaning dung and osme meaning smell and refers to the dung-like smell of some species.
Repens is from the Latin repe meaning to creep referring to the creeping habit of bush as the stems take root where they contact the ground.
Looking-glass Bush refers to its shiny leaves.

Other Names:

Mirror Plant or Mirror Bush because of its shiny leaves.

Summary:

A shiny leaved, many branched, evergreen shrub, 0.5-8 m tall with sprays of small white flowers.

Description:

Cotyledons:

Two.

First leaves:

Leaves:

Opposite.
Stipules - Small, pointed, triangular, toothed, sheathing. Interpetiolar.
Petiole - 5-20 mm long.
Blade - Oval to roundish. 20-80 mm long x 10-50 mm wide. Slightly fleshy to leathery. Topside dark green and shiny. Lower side pale green and dull. The leaves turn black when dried. Mid vein prominent. On the underside there are pits (domatia) where the veins branch. Tip rounded to slightly indented with a tiny point. Sides curved. Base abruptly tapering. Hairless.

Stems:

0.5-8 m tall. Initially smooth and light green to grey and become grey to brown and rough with age. Forms roots where stems contact the ground. Young stems are square and become round with age. Hairy or hairless.

Flower head:

Male flowers usually in dense, compound clusters in leaf axils. Female flowers usually a cluster of 3 flowers in leaf axils. Clusters on a short, simple stalk (peduncle).

Flowers:

Small, white to greenish, tubular and 3 mm long for male flowers and 5 mm long for female flowers. Male and female flowers usually on separate plants.
Ovary - Inferior. Female flowers have a 2 celled, each with a single erect seed (ovule). Male flowers have an imperfect or abortive style and no ovary.
Style - divided almost to the base with 2 long, stout lobes.
Calyx - Tiny, 4-5 toothed. Persistent in fruit.
Petals - White, tubular with 4-5 lobes that are about as long as the tube in male flowers and shorter than the tube in female flowers.
Stamens - Attached at the base of the corolla tube. Stick out of the end of the flower (exerted) in male flowers. Small and imperfect in female flowers.
Anthers -

Fruit:

Fleshy globular to egg-shaped, berry (drupe), 6-10 mm diameter with 1-2 seeds. Initially green and ripening to orange-red. Tip is flattened or depressed.

Seeds:

Roots:

Mainly shallow with a woody, branching taproot that is thickened at the crown.

Key Characters:

Woody shrub
Pits (domatia) at vein junctions on the underside of the leaves.
Leaves opposite, somewhat fleshy with a shiny upper surface and a dull underside. 10-80 mm long, >10 mm wide. Apex obtuse, truncate or emarginate. Base abruptly tapered.
Small scarious free or connate stipules
Flowers unisexual, in clusters and not contracted into a head.
Flowers along branches behind leaves or on axillary flower bearing, short shoots.
Corolla lobes valvate (in bud).
Ovules solitary and erect from base in each cell of the ovary.
Micropyle inferior.
Fruit a berry-like drupe.
Albumen copious
Adapted from John Black, Gwen Harden.

Biology:

Life cycle:

Fast growing long lived perennial shrub or small tree.

Physiology:

Tolerates salt spray, wind, drought, frost and fire.

Reproduction:

Seed and stems taking root where they touch the ground.

Flowering times:

Spring to summer in NSW.
September - December in Victoria.

Seed Biology and Germination:

Seed germinates readily whenever moisture is present and recruitment is high in protected locations. It will germinate in leaf litter.
Female bushes set large amounts of seed.

Vegetative Propagules:

Stems and rootstocks.

Hybrids:

At least 4 varieties and some have variegated leaves.

Allelopathy:

Population Dynamics and Dispersal:

Spread by seed eaten by birds and animals (foxes and possums) and dumping of garden refuse. Often found under trees where birds roost.
Tends to establish most readily in partially shaded areas with disturbed soil or understorey.
In exposed, windy areas the plants become somewhat prostrate and layering of the stems occurs.

Origin and History:

New Zealand.
Introduced as a hedge plant or ornamental.

Distribution:

ACT, NSW, SA, TAS, VIC, WA.
New Zealand.
USA.
Naturalised at Albany, Esperance and Perth.

Courtesy Australia's Virtual Herbarium.

Habitats:

Often found in coastal locations, on beaches, headlands and islands.

Climate:

Warm temperate.
Tends to be more invasive in areas with an annual rainfall greater than 600 mm.
Grows in shade and full sun areas.

Soil:

Often found on sandy soils and rocky outcrops but tolerates a wide range of soil types.

Plant Associations:

Dry coastal vegetation, heathland, dry and wet sclerophyll forest, warm temperate rainforest, freshwater wetlands, rocky outcrops.

Significance:

Beneficial:

Ornamental, salt tolerant, hedge and windbreak plant.
Leaves used to make children's whistles.

Detrimental:

Minor environmental weed.

Toxicity:

Not reported as toxic.

Symptoms:

Treatment:

Legislation:

None.

Management and Control:

Fire kills the top growth but it readily regenerates from the roots.
Cutting is ineffective as it vigorously regrows from the base.

Thresholds:

Eradication strategies:

Hand pull seedlings. Roots need to be dug up and removed on larger plants to prevent regrowth.
Cut and paint stumps immediately with neat glyphosate. Larger bushes can be drilled or frilled and treated with glyphosate.
Prunings need to be burnt to prevent them taking root.
Target female plants first to reduce seed production.

Spraying is most effective on small plants and wetting agents are required to wet the leaves.
Infestations are usually controlled by cutting and painting stems, hand pulling seedlings and respraying regrowth until just wet in the following season with 1 L glyphosate450 plus 250 mL Pulse® Penetrant in 100 L of water.

Herbicide resistance:

Biological Control:

Related plants:

Karamu (Coprosma robusta) is naturalized in Victoria and Tasmania. It looks very similar but has smaller fruits and no pits at the vein junctions on the underside of the leaves.
Coprosma lucida
Same family as Bedstraw and Cleavers (Galium species) and Field Madder (Sherardia arvensis)

Plants of similar appearance:

References:

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia) P796.

Blood, K. (2001). Environmental weeds: a field guide for SE Australia. (CH Jerram & Associates, Australia). P48-49. Photos.

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume 3. P503. Diagram.

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). 275.1.

Muyt, A. (2001). Bush Invaders of South-East Australia: a guide to the identification and control of environmental weeds found in South East Australia. (R.G and F.J. Richardson, Australia). P168-169. Photos.

Randall, J.M. and Marinelli, J. (1996) Invasive Plants. (Brooklyn Botanic Gardens Inc. Brooklyn). P. Photo.

Acknowledgments:

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