miconia

Miconia calvescens
Tree
Opposite
Simple
White
Pink
Green
Purple
Discoloured

A tree growing up to 15 m tall and bearing very large leaves (usually 60-70 cm long). Its alternately 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.

Common names 
Also known as: miconia, bush currant, purple plague, velvet tree, velvetleaf,
Family 
Melastomataceae
Deciduous 
No
Flowering time 
Variable
Native/Exotic 
Exotic
Origin 
Native to Mexico, parts of Central America and tropical South America.
Notifiable 
No
State declaration 
Class 1
Council declaration 
Class E - Early detection and eradication
Known 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.

Impact and control methods 

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.

Stem 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 fruits 

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.

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.