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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
Other Impacts
Legislation
Management
Similar Species
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stems and leaves (Photo: Forest and Kim Starr, USGS)

leaves and flower clusters (Photo: Forest and Kim Starr, USGS)

Asystasia gangetica subsp. micrantha

Scientific Name

Asystasia gangetica (L.) T. Anderson subsp. micrantha (Nees) Ensermu

Synonyms

Asystasia coromandeliana var. micrantha Nees
Asystasia gangetica (L.) T. Anderson

Family

Acanthaceae

Common Names

Chinese violet, coromandel, creeping foxglove, Ganges primrose, Philippine violet

Origin

This sub-species is native to sub-Saharan Africa (i.e. Ethiopia, Kenya, Tanzania, Uganda, Cameroon, Equatorial Guinea, Zaire, Ivory Coast, Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Mali, Nigeria, Senegal, Sierra Leone, Togo, Angola, Malawi, Mozambique, Zambia, Zimbabwe, Botswana, Namibia, South Africa and Swaziland).

Cultivation

This plant has been cultivated as a garden ornamental, particularly in warmer regions.

Naturalised Distribution

Locally naturalised in eastern Australia (i.e. in the coastal districts of central New South Wales and in south-east Queensland, currently not very widespread. So far, populations have been detected at Newcastle and at nearby Anna Bay and Fern Bay.

It may also be present amongst populations of Asystasia gangetica in northern Australia, as not all states recognise subspecies of this species. Also naturalised overseas in south-eastern Asia (i.e. Malaysia, Indonesia and Papua New Guinea), tropical America and Oceania.

Habitat

A potential weed of distrubed sites, waste areas, roadsides, crops, plantations, open woodlands, forest margins and coastal habitats in the warmer temperate, sub-tropical and tropical regions of Australia. It is currently found mainly on coastal sandy soils in the warmer temperate regions of New South Wales.

Habit

A long-lived (i.e. perennial) herbaceous plant that is usually a mat-forming creeper (i.e. prostrate or decumbent) growing less than 0.5 m tall. However, it can also sprawl or clamber over supporting vegetation to a height of 3 m or more.

Distinguishing Features

Stems and Leaves

The stems are lightly hairy (i.e. sparsely pubescent) and develop roots (i.e. adventitious roots) where the joints (i.e. nodes) come into contact with moist soil.

The bright green leaves are arranged in opposite pairs along the stems and are also sparsely hairy (i.e. sparsely pubescent). These leaves (2.5-8 cm long and 1.5-4 cm wide) are egg-shaped in outline (i.e. ovate), heart-shaped (i.e. cordate) or oval (i.e. elliptic) in shape and have paler green undersides. They are borne on stalks (i.e. petioles) 8-20 mm long and have entire or slightly bluntly toothed (i.e. crenate) margins with pointed tips (i.e. acute apices).

Flowers and Fruit

The tubular flowers (1.8-3.5 cm long and about 3 cm across) are borne in elongated clusters (i.e. racemes) up to 10 cm long and are arranged along one-side of the stem. The flowers are borne on short stalks (i.e. pedicels) 2-3 mm long and have five sepals (7-9 mm long) that are fused together at the base (i.e. into a clayx tube). The petals are also fused into a tube (i.e. corolla tube) for most of their length (up to 25 mm) and have five spreading lobes (i.e. corolla lobes). These petals are mostly white in colour, but the bottom petal lobe has purple blotches in two parallel lines on its inside. The flowers also have four yellow stamens and an ovary topped with a long style that ends in a tiny two-lobed stigma. Flowers and fruit can be present year round, but are mainly produced during warmer and wetter conditions.

The fruit are elongated or club-shaped (i.e. clavate) capsules and contain four seeds. These capsules (13-36 mm long) have two compartments (i.e. two seeds in each compartment) and turn from green to bown in colour as they mature. The flattened seeds (about 5 mm long and 1 mm wide) are bone-coloured to brownish-black.

Reproduction and Dispersal

This species reproduces by seed and also vegetatively via stem segments.

The seeds are explosively released from the capsules when they are mature and can be propelled short distances. The trailing stems produce roots when they come into contact with moist soil and can spread an infestation laterally. The main method of dispersal over long distances is by human activities (e.g. mining, gardening, landscaping, roadworks and the dumping of garden waste), though spread may be mitigated by water and animals.

Environmental Impact

Chinese violet (Asystasia gangetica subsp. micrantha) is on the Alert List for Environmental Weeds. This is a list of invasive plants that are in the early stages of establishment in Australia, and are thought to threaten biodiversity and have the potential to seriously degrade native ecosystems. This species forms dense mats of vegetation that smother other ground plants and displaces native flora. It also reduces the availability of habitat for native plants and animals and therefore reduces biodiversity. It is regarded as an important emerging environmental weed in New South Wales.

Other Impacts

Chinese violet (Asystasia gangetica subsp. micrantha) is a weed of rubber, oil palm and coffee plantations, and other crops, in south-eastern Asia. If it became widely established it could potentially affect summer crops and plantation crops in northern Australia. As it competes effectively for soil nutrients, it could reduce the productivity and increase the management costs of crops in northern agricultural regions.

Legislation

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

Management

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

Similar Species

Chinese violet (Asystasia gangetica subsp. micrantha) is very similar to another form of Chinese violet (i.e. Asystasia gangetica subsp. gangetica). These sub-species can be distinguished by the following differences:

A native species (i.e. Asystasia australasica), which is only found in far northern Queensland, is also very similar.

Note: The entirely white-flowered form of Chinese violet (Asystasia gangetica subsp. gangetica) is sometimes also known as Asystasia gangetica 'Alba'.