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 Other Impacts Legislation Similar Species

Scientific Name

Abrus precatorius subsp. africanus Verdc.

Synonyms

Abrus precatorius L.

Abrus precatorius L. subsp. precatorius (misapplied)

Family

Fabaceae (Queensland, the ACT, Victoria, Tasmania and the Northern Territory)

Fabaceae:  subfamily Faboideae (New South Wales)

Leguminosae (South Austrlaia)

Papillionaceae (Western Australia)

Common Names

bead vine, black-eyed Susan, coral bead plant, coral bean, crabs eye, crab's eye, crab's eye creeper, crab's eye vine, crab's eyes, crab's-eye, crab's-eye creeper, crabs-eye creeper, gidee -gidee, Indian licorice, jequirity, jecquirity bean, jequirity seeds, licorice vine, love bean , lucky bean, prayer beads, prayer bean, precatory pea, red beadvine, rosary bean, rosary pea, weatherplant, weathervine

Origin

Native to tropical Africa, Madagascar and some islands in the western Indian Ocean (Mauritius and the Seychelles)

Cultivation

Crab's eye creeper (Abrus precatorius subsp. africanus) has been widely cultivated as a garden ornamental, largely because of its attractive and decorative bright red and black coloured seeds.

Naturalised Distribution

The plant is becoming widely naturalised in south-eastern Queensland. It has also been recorded from north-eastern New South Wales and the coastal districts of central Queensland.

Habitat

A common weed of roadsides, old gardens, disturbed sites, waste areas and waterways (i.e. riparian areas) in the higher rainfall areas of sub-tropical eastern Australia. It has also been reported from open woodlands, rainforest margins and coastal fore-dunes in this region.

In Hawaii it has become naturalised in dry disturbed sites, while in Florida it has invaded undisturbed pine forests and other open woodlands.

Habit

A slender, but long-lived (i.e. perennial), climbing plant that grows up over supporting vegetation adn can reach up to 10 m or more in height.

Distinguishing Features

• a climbing plant with slender twining stems.
• its once-compound leaves have several to numerous pairs of small leaflets.
• its pea-shaped whitish, pink or purplish flowers (about 10 mm long) are borne in dense, slightly elongated, clusters.
• its relatively short pods (20-35 mm long) have a rough surface texture.
• these pods split open when mature to reveal several bright red and black coloured seeds (5-7 mm long).

Stems and Leaves

Older stems are covered in a smooth-textured or wrinkled brown bark. Younger stems are generally smooth, covered in tiny hairs (i.e. pubescent), and greenish in colour.

The alternately arranged leaves (5-13 cm long) are once-compound (i.e. pinnate) with 5-17 pairs of leaflets. These leaflets (5-25 mm long and 2-8 mm wide) are mostly hairless (i.e. glabrous), oblong in shape, and have rounded tips (i.e. obtuse apices).

Flowers and Fruit

The small whitish, pink, mauve or purplish pea-shaped flowers (about 10 mm long) are borne in dense slightly elongated clusters. These flower clusters are usually arranged on stalks (i.e. peduncles) that emanate from the leaf forks (i.e. axillary racemes). Individual flowers have five small green sepals, which are fused together at the base into a short tube (i.e. calyx tube). They have a large upper petal (i.e. standard), two side petals (i.e. wings) and two lower petals that are fused together and folded lengthwise (i.e. a keel).

The fruit is a flat and realtively broad pod (20-35 mm long and 12-15 mm wide) with a sharp point (i.e. beak). These pods are sparsely covered in hairs and have a rough texture (i.e. they are tuberculate). When mature, these brown pods split open and curl back to reveal several (usually 3-7) oval-shaped (i.e. ellipsoid) seeds. The very distinctive seeds (5-7 mm long and 4-5 mm wide) are bright scarlet-red in colour with a large black spot. They are smooth in texture, glossy in appearance and generally remain on the plant for some time (i.e. several months).

Reproduction and Dispersal

This species reproduces mainly by seed. These seeds are thought to be mostly bird-dispersed, but it is likely that they are also spread along waterways during floods and in dumped garden waste.

Environmental Impact

Crab's eye creeper (Abrus precatorius subsp. africanus) is regarded as an environmental weed in New South Wales and south-eastern Queensland. It is currently of most concern in north-eastern New South Wales, where it is a relatively recent introduction, but it is much more common and widespread in south-eastern Queensland.

This species has been reported in various types of open woodlands (e.g. banksia and eucalypt forests) in the coastal districts of northern New South Wales. It appears on the regional environmental weed list for north-eastern New South Wales, developed by the Bushland Friendly Nursery Scheme, and hence also appears on several local environmental weed lists in this region (e.g. in Ballina Shire, Lismore City and Coffs Harbour City councils).

Crab's eye creeper (Abrus precatorius subsp. africanus ) is also one of the "exotic vines and scramblers" whose invasion of native plant communities is listed as a "key threatening process" in New South Wales. Such species are of concern because they may act as transformer species, altering the nature of the plant communities that they invade. Exotic vines and scramblers smother existing vegetation, both in the ground layer and canopy, altering the light climate and suppressing the regeneration of native species.

Until recently, crab's eye creeper (Abrus precatorius) was often regarded as being native to south-eastern Queensland, or as being introduced here from northern Queensland, and was not treated as a serious threat. However, now that it is known to be an exotic form of this species, crab's eye creeper (Abrus precatorius subsp. africanus) is beginning to be treated with more concern as a potentially invasive plant. Populations of this weed are becoming more common and widespread in the region, and are often seen in riparian areas and revegetation sites in suburban Brisbane (e.g. along Enoggera Creek in The Gap and the along the Brisbane River in St. Lucia). Infestations are also being actively controlled on Fraser Island.

Crab's eye creeper (Abrus precatorius) is also regarded as a serious invasive weed in some parts of the USA, particularly throughout the central and southern parts of Florida, where it is noted to establish well in disturbed drier forests and spread rapidly after fires.

Other Impacts

The seeds of this species are extremely toxic to humans and livestock (e.g. cattle and horses).

Legislation

This species is not declared or considered noxious by any State or Territory.

Similar Species

Because of its very distinctive seeds, crab's eye (Abrus precatorius) is rarely confused with other species. However, the introduced form of this species (i.e. Abrus precatorius subsp. africanus) is extremely similar to the native form which grows in northern Australia (i.e. Abrus precatorius subsp. precatorius). These two subspecies can be distinguished by the following differences:

• Abrus precatorius subsp. africanus has smaller pods (20-35 mm long) with a rough surface texture (i.e. they are tuberculate).
  
• Abrus precatorius subsp. precatorius has larger pods (30-50 mm long) with a relatively smooth surface texture.

Giddy giddy (Adenanthera abrosperma), a native tree from northern Queensland, has almost identical red and black seeds. However, this plant can be easily distinguished by its arborescent habit, globular flower clusters, and twice-compound (i.e. bipinnate) leaves.