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Scientific Name
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
Print Fact Sheet
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Click on images to enlarge

infestation (Photo: Sheldon Navie)

habit (Photo: Sheldon Navie)

habit (Photo: Sheldon Navie)

the large palmately lobed leaves (Photo: Sheldon Navie)

leaf with nime lobes (Photo: Sheldon Navie)

flower cluster with separate red female flowers and yellow male flowers (Photo: Sheldon Navie)

close-up of male flowers (Photo: Forest and Kim Starr, USGS)

immature fruit (Photo: Sheldon Navie)

close-up of immature fruit (Photo: Forest and Kim Starr, USGS)

mature fruit (Photo: Forest and Kim Starr, USGS)

close-up of seeds (Photo: Steve Hurst at USDA PLANTS Database)

young seedling with large cotyledons (Photo: Sheldon Navie)

young plant (Photo: Sheldon Navie)

leaves of Ricinus communis 'Carmencita' (Photo: Sheldon Navie)

immature fruit of Ricinus communis 'Carmencita' (Photo: Sheldon Navie)

Ricinus communis

Scientific Name

Ricinus communis L.

Family

Euphorbiaceae

Common Names

African coffee tree, castor, castor bean, castor bean plant, castor oil bush, castor oil plant, castor oil tree, castorbean tree, castor-oil plant, maple weed, Palma Christi, Palma-christi, wonder tree

Origin

This species probably originated in Africa, but is now widespread throughout the tropical and sub-tropical regions of the world.

Cultivation

This species is still occasionally seen growing in gardens, particularly cultivars with reddish-coloured leaves and fruit (e.g. Ricinus communis 'Carmencita Red').

Naturalised Distribution

A very widespread species that is most commonly naturalised in the coastal and sub-coastal districts of Queensland, New South Wales and south-western Western Australia. Scattered populations also occur throughout other parts of these states. It has also been recorded from the Northern Territory, South Australia, Victoria, and several offshore island territories (i.e. Norfolk Island, Christmas Island, Lord Howe Island and the Cocos Islands).

Widely naturalised overseas, including in the USA, Mexico, South America, New Zealand and on numerous Pacific islands (e.g. American Samoa, Western Samoa, Fiji, Guam, Hawaii, French Polynesia, the Cook Islands, the Galápagos Islands, Kiribati, Nauru, New Caledonia, Niue, Palau, the Solomon Islands and Tonga).

Habitat

A weed of creek banks (i.e. riparian areas), dry riverbeds, waterways, roadsides, railways, disturbed sites, pastures, gardens, neglected suburban areas and other waste areas in tropical, sub-tropical, temperate and sometimes also semi-arid environments.

Habit

A long-lived (i.e. usually perennial) shrub often growing up to 3 m tall, but occasionally reaching up to 10 m in height.

Distinguishing Features

Stems and Leaves

The thick stems are generally greyish-green in colour (i.e. glaucous), but sometimes they have a reddish tinge. They are moderately branched, hollow, and hairless (i.e. glabrous). Older stems turn greyish in colour and may become somewhat woody.

The alternately arranged hairless (i.e. glabrous) leaves are borne on stalks (i.e. petioles) 10-30 cm long and have very large leaf blades (10-70 cm long and 15-60 cm wide). The leaf stalks (i.e. petioles) are usually attached directly to the undersides of the leaves (i.e. the leaves are peltate). The leaf blades have 5-10 (usually 7-9) spreading finger-like lobes (i.e. the leaves are palmately-lobed) with pointed tips (i.e. acute apices). Each of the lobes has a prominent vein running down its centre and its margins are finely toothed (i.e. serrate). Young leaves are often dark red or purplish in colour and usually somewhat glossy in appearance, while older leaves are green or bluish-green in colour.

Flowers and Fruit

The large elongated flower clusters (8-15 cm long) are usually produced near the tips of the branches (i.e. in terminal, or sometimes axillary, racemes). Separate male and female (i.e. unisexual) flowers are present in these clusters (i.e. the plants are monoecious). Both flower types are borne on stalks (i.e. pedicels) up to 10 mm long and do not have any petals, but they do have three to five small sepals (5-8 mm long). The cream or yellow male (i.e. staminate) flowers are produced at the base of the flower clusters and have about 100 stamens. The female (i.e. pistillate) flowers have large three-segmented ovaries with three feathery bright red styles and are produced at the top of the flower clusters. Flowering occurs all year round but is most abundant during late spring, summer and early autumn (i.e. from November to March).

The egg-shaped (i.e. ovoid), rounded (i.e. globular), or slightly three-lobed fruit are greenish, greenish-red or bright red in colour when young and covered in soft blunt spines. These capsules (10-30 mm across) turn brown as they mature and divide into three segments, each containing a single seed. The seeds are mottled grey and brown (10-17 mm long and 6-10 mm wide), smooth in texture, somewhat oval in shape (i.e. oblong-ellipsoid), and have a small fleshy projection (i.e. aril) at one end.

Reproduction and Dispersal

This plant reproduces entirely by seed.

The seeds are explosively released when the fruit are mature, thereby aiding their spread. They are also often dispersed by floodwaters and animals (e.g. rodents and birds). Humans also spread the seeds in dumped garden waste, mud, soil and on vehicles and machinery.

Environmental Impact

Castor oil plant (Ricinus communis) is regarded as an environmental weed in Queensland, New South Wales, the Northern Territory, Western Australia, Victoria, South Australia and on Christmas Island. It was also recently listed as a priority environmental weed in at least one Natural Resource Management region.

Other Impacts

The seeds of this species are extremely toxic to humans and livestock.

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

Castor oil plant (Ricinus communis) can be confused with bellyache bush (Jatropha gossypiifolia) and physic nut (Jatropha curcas). These species can be distinguished by the following differences: