Weeds of Australia - Fact Sheet

Top Scientific Name Synonyms Family Common Names Origin Cultivation Naturalised Distribution Habitat Habit Distinguishing Features Stems and Leaves Flowers and Fruit Reproduction and Dispersal Environmental Impact Legislation Management Similar Species

Scientific Name

Miconia calvescens DC.

Synonyms

Miconia magnifica Triana

Family

Melastomataceae

Common Names

bush currant, miconia, purple plague, velvet tree, velvetleaf

Origin

Native to Mexico, parts of Central America (i.e. Guatemala and Panama) and tropical South America (i.e. Bolivia, Colombia, Ecuador, Peru, Paraguay and south-eastern Brazil).

Cultivation

A garden ornamental that has occasionally been grown in the tropical regions of Australia, largely for its spectacular purplish-coloured leaves.

Naturalised Distribution

Miconia (Miconia calvescens) is not yet widely naturalised in Australia. It has been recorded at a few locations in coastal far northern Queensland (i.e. at Cairns, Mossman and Kuranda).

Also naturalised in tropical Asia (e.g. Sri Lanka), Melanesia, French Polynesia, New Caledonia and Hawaii.

Habitat

A potential weed of tropical and sub-tropical environments. It invades closed forests, rainforest margins, roadsides, creek-banks and disturbed sites.

Habit

An evergreen tree usually growing 4-8 m tall, but occasionally reaching up to 16 m in height.

Distinguishing Features

• a tree growing up to 15 m tall and bearing very large leaves (usually 60-70 cm long).
  
  
• its oppositely arranged leaves are usually green above and bright purplish below.
  
  
• these leaves have three distinct veins that run almost parallel from the base to the tip of the leaf.
  
  
• its numerous small white or pinkish flowers are borne in large clusters at the tips of the branches.
  
  
• its small fleshy berries (about 6-7 mm across) turn black, bluish-black or purplish when mature.

Stems and Leaves

The young stems are greenish in colour and somewhat four-angled (i.e. quadrangular), but turn brown and become rounded (i.e. terete) as they mature. The younger branches are usually covered in tiny star-shaped (i.e. stellate) hairs.

The oppositely arranged leaves are very large (often 17-40 cm long and 7-25 cm wide, but sometimes up to 1 m long) and borne on stalks (i.e. petioles) 2-6 cm long. These leaves usually have green upper surfaces and striking purplish coloured undersides. They also have three distinct veins that run almost parallel from the base to the tip of the leaf. The leaf blades are somewhat oval in shape (i.e. oblong-elliptic) with pointed tips (i.e. shortly acuminate apices). They are mostly hairless (i.e. glabrous) and have entire or very finely toothed margins.

Flowers and Fruit

The numerous small flowers are borne in large branched clusters (20-50 cm long) at the tips of the branches (i.e. in terminal panicles). These flowers are short-lived and each is borne directly on the branches of the flower clusters (i.e. the flowers are sessile). They have five tiny sepals (1-3 mm long) and the base of the flower is swollen (i.e. into a hypanthium 2-2.7 mm long). They also have five white or pinkish coloured petals (2-3 mm long and 1-2 mm wide), several stamens (3-4 mm long), and a style (5-7 mm long) topped with a stigma.

The fruit are small fleshy berries (about 6-7 mm across) that are arranged in large clusters (i.e. infructescences containing up to 500 fruit). These berries turn black, bluish-black or purplish in colour as they mature. Each fruit contains around 140-230 tiny seeds (about 0.7 mm long and 0.5 mm wide).

Reproduction and Dispersal

This species reproduces mostly by seeds which are primarily dispersed by fruit-eating (i.e. frugivorous) birds. Other dispersal agents include wind, water, vehicles, and other animals (i.e. small mammals). Vegetative reproduction via layering and re-sprouting sometimes also occurs.

Environmental Impact

Miconia (Miconia calvescens) is regarded as an environmental weed in Queensland and as a potential environmental weed in northern New South Wales. It is listed as a priority environmental weed in at least one Natural Resource Management region, and a national eradication program commenced in Australia in 2001.

Legislation

This species is declared under legislation in the following states and territories:

• New South Wales: Class 1- a state prohibited weed. The presence of the weed on land must be notified to the local control authority and the weed must be fully and continuously suppressed and destroyed (throughout the entire state). This declaration also applies to all miconia species (i.e. Miconia spp.).
  
  
• Northern Territory: C - not to be introduced into the Territory. This declaration also applies to all miconia species (i.e. Miconia spp.).
  
  
• Queensland: Class 1 - introduction into the state is prohibited, and landowners must take reasonable steps to keep land free of this species (throughout the entire state). It is also illegal to sell a declared plant or its seed in this state. This declaration also applies to all miconia species (i.e. Miconia spp.).
  
  
• Western Australia: P1 - trade, sale or movement into the state prevented, and P2 - to be eradicated (throughout the entire state). This declaration also applies to all miconia species (i.e. Miconia spp.).

Management

For information on the management of this species see the following resources:

• the Biosecurity Queensland Fact Sheet on this species, which is available online at http://www.dpi.qld.gov.au.
  
  
• the New South Wales Department of Primary Industries Weed Alert on this species, which is available online at http://www.dpi.nsw.gov.au.

Similar Species

Miconia (Miconia calvescens) is very distinctive, but it may be confused with two other Miconia species that have also recently become naturalised in northern Queensland (i.e. Miconia nervosa and Miconia racemosa). These species can be distinguished by the following differences:

• Miconia calvescens has very large leaves (often 17-40 cm long and 7-25 cm wide and sometimes larger) that are borne on stalks (i.e. petioles) 2-6 cm long. The undersides of its leaves are bright purple in colour and mostly hairless (i.e. glabrous). Its leaves have three obvious veins that run from the base to the leaf tip.
  
  
• Miconia nervosa has relatively large leaves (up to 25 cm long) that are borne on stalks (i.e. petioles) 1-2 cm long. The undersides of its leaves are pale green in colour and the veins, in particular, are densely covered in stiff (i.e. strigose) hairs. Its leaves have five obvious veins, two of which arise part of the way up the leaf blade (i.e. 2-8 cm from the base).
  
  
• Miconia racemosa has relatively large leaves (up to 25 cm long) that are borne on stalks (i.e. petioles) 1-4.5 cm long. The undersides of its leaves are green in colour and mostly hairless (i.e. glabrous). Its leaves have five obvious veins that run from the base to the leaf tip.