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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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Click on images to enlarge

habit during the wet season (Photo: Sheldon Navie)

habit during the dry season (Photo: Sheldon Navie)

leaves (Photo: Sheldon Navie)

leaves (Photo: Sheldon Navie)

close-up of leaf underside (Photo: Sheldon Navie)

flower cluster (Photo: Sheldon Navie)

close-up of flowers (Photo: Sheldon Navie)

immature fruit (Photo: Sheldon Navie)

mature fruit (Photo: Sheldon Navie)

old fruit (Photo: Sheldon Navie)

close-up of seeds (Photo: Sheldon Navie)

seedling (Photo: Sheldon Navie)

young plant (Photo: Sheldon Navie)

Jatropha curcas

Scientific Name

Jatropha curcas L.

Synonyms

Curcas curcas (L.) Britt.

Family

Euphorbiaceae

Common Names

American purging nut, Barbados nut, Barbados purging nut, bed bug plant, big purge nut, black vomit nut, Brazilian stinging nut, Cuban physic nut, curcas bean, hell oil, physic nut, purge nut, purging nut, purging nut tree, tuba

Origin

Native to Mexico, the Caribbean, Central America (i.e. Belize, Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua) and South America (i.e. Brazil, Bolivia, Peru, Argentina and Paraguay).

Cultivation

Physic nut (Jatropha curcas) was deliberately introduced into Australia at some time in the late 1800's. It has mainly been cultivated as a hedging plant or garden ornamental around mining sites and homesteads in the northern parts of Australia.

Naturalised Distribution

This species has a scattered distribution throughout the coastal and sub-coastal districts of northern and north-eastern Australia. It is most common in the north-western parts of the Northern Territory (particularly around Darwin) and in northern Queensland. It is occasionally also naturalised in the coastal regions of central and southern Queensland and is present in the inland regions of the Northern Territory. The two main infestations in the Northern Territory are located near Pine Creek and Kapalga.

Habitat

A weed of tropical and sub-tropical environments that is found in disturbed sites, pastures, open woodlands, waste areas, abandoned gardens and along roadsides.

Habit

An upright (i.e. erect) shrub or small tree usually growing 2-4 m tall. This species often loses its leaves during the dry season (i.e. it is deciduous).

Distinguishing Features

Stems and Leaves

The older stems are thick and softly woody, with the younger ones are sometimes slightly hairy (i.e. puberulent).

The leaves are alternately arranged along the stems and borne on stalks (i.e. petioles) 6-14 cm long. They are relatively large (10-19 cm  long and 5-15 cm wide) and smooth and shiny in appearance. These leaves have heart-shaped (i.e. cordate) bases and three or five shallow lobes with rounded or pointed tips (i.e. obtuse to acute apices).

Flowers and Fruit

The pale yellow to greenish coloured flowers are small and inconspicuous. They are borne in loose clusters on short stalks (i.e. peduncles) in the forks (i.e. axils) of the upper leaves or at the tips of the branches (i.e. in terminal or axillary panicles). Flowering occurs throughout the year, but is most abundant during the wet season.

The fruit is a fleshy capsule that is initially green in colour, but turns yellow and then dark brown as it matures. These fruit (3-4 cm long) are oval (i.e. ellipsoid) or almost round (i.e. sub-globular) in shape and usually contain three large seeds. The smooth textured seeds (17-20 mm long) are mostly brown or black in colour, with some fine yellow stripes. They are hard and slightly bean-shaped (i.e. reniform).

Reproduction and Dispersal

This species reproduces by seed and also vegetatively via suckers originating from the roots and crown.

Seeds may be spread short distances when they are explosively released, while most long range dispersal probably occurs in water or in mud adhering to animals and vehicles. The spread of this species is also aided by its deliberate cultivation in home gardens.

Environmental Impact

Physic nut (Jatropha curcas) is not a particularly aggressive weed, and tends to spread relatively slowly. However, it is drought resistant and will grow under a wide range of climatic and soil conditions. It is regarded as an environmental weed or potential environmental weed in many parts of northern Australia. Plants are usually found in disturbed areas, especially around abandoned homesteads and mines.

Physic nut (Jatropha curcas) competes with native species or pasture plants can eventually form dense thickets or colonies. If it is allowed to establish widespread populations over time, it may threaten some of Australia's rangeland communities. For example, it is regarded as posing a threat to biodiversity in the Einasleigh and Desert Uplands bioregion in inland northern Queensland.

Other Impacts

The fresh seeds are highly poisonous to humans, especially to children, and can be mistaken for peanuts. They are also toxic to livestock, though few instances of stock poisoning have been reported in Australia.

Physic nut (Jatropha curcas) competes with pasture plants and dense thickets may reduce pasture productivity. It may also act as an alternative host for insect pests of cotton crops.

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

Physic nut (Jatropha curcas) is very similar to bellyache bush (Jatropha gossypiifolia) and relatively similar to castor oil plant (Ricinus communis). These three species can be distinguished by the following differences: