Caesalpinia subtropica, Caesalpinia scortechinii Summary Mysore thorn Caesalpinia decapetala originates from tropical and eastern Asia but is now a serious weed in many locations such as South Africa, Tanzania, Zimbabwe, Hawaii, Portugal, New Zealand and Norfolk Island. It has become a major invasive plant in South Africa and Hawaii, where it has the capability to take over large areas of agricultural land, limiting animal movement. This sprawling, thorny and noxious shrub also invades forest margins, smothering native vegetation. It often forms dense thickets. The stems are covered with minute golden-hair and thorns which are straight or hooked, numerous and not in regular rows or confined to nodes. The leaves are dark green, paler underneath, not glossy, up to 30 cm long with leaflets up to 8 mm wide.
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Caesalpinia sepiaria Roxb. Witt pers. It is still being spread in the region as a life fence hedge. The young branches are densely covered with tiny brownish or golden-coloured hairs and have numerous sharp recurved thorns. Older stems are thicker, greyish-brown in colour, and have larger thorns. The leaves are twice-compound bipinnate , alternately arranged , and have a pair of small leafy structures stipules at their base. These stipules mm long are egg-shaped in outline with broad end at base ovate , but taper to a point they have acute apices.
The leaves are borne on stalks petioles cm long. The extension of this stalk the rachis is slightly hairy puberulent , prickly, and bears pairs of branchlets pinnae.
Each of these branchlets pinnae has pairs of leaflets pinnules. The leaflets mm long and mm wide are oblong or obovate egg-shaped in outline but with the narrower end at the base and somewhat hairy pubescent on both sides, dark green above, paler below. The flowers are usually pale yellow or yellow in colour occasionally whitish , with five petals mm long , five sepals mm long , ten stamens mm long , and a style mm long topped with a cup-shaped cupular stigma. Four of the petals are almost circular orbicular in shape, but the upper petal is smaller and narrower than the others.
The flowers are borne on stalks pedicels mm long and arranged in upright erect , elongated , clusters in some cases they may reach 20 cm long at the tips of the branches in terminal racemes. The fruits are flattened, oblong , pods with a small projection beak at one end. These woody pods cm long and about 25 mm wide are hairy pubescent and turn from green to brown as they mature. When they are fully mature, they split open to release rounded globular seeds.
These seeds mm across are brown and black in colour, persisting for many months and scattering seeds as they break open are scattered as the pod opens. Reproduction and dispersal This plant reproduces by seeds, which may be dispersed by animals e. The pods may also float on water. This species has been widely dispersed as hedge plants because they grow well in that situation and form an almost impenetrable barrier to livestock and people. Similar species Caesalpinia decapetala is quite similar to Caesalpinia gilliesii dwarf poinciana and Caesalpinia pulcherrima pride of Barbados.
These species can be distinguished by the following differences: C. Its yellow flowers have very long stamens 60 mm or more long with distinctive bright red filaments. The elongated flower clusters racemes are covered in sticky hairs they are glandular pubescent and the flower petals are relatively large mm long compared with C.
But, its bright yellow or red and yellow flowers have very long stamens 60 mm or more long with yellow or bright red filaments unlike C. The elongated flower clusters racemes are hairless glabrous and the showy flowers have relatively large petals more than 25 mm long. Economic and other uses Caesalpinia decapetala has been introduced as a live fence. In parts of Uganda especially near protected areas, this species is used as a live hedge around gardens to keep off pests especially baboons and other primates due to its strong tough thorns D.
Hafashimana pers. It is also used for ornamental purposes. It invades forest edges and gaps preventing regeneration of native species and climbs into canopies and causes canopy collapse or death of trees. It can also invade native vegetation, pastures and grasslands and adversely affect the movement of livestock and some species of wildlife. Its dense thickets can restrict water flow, access and downstream movement of flood debris, leading to increased upstream flood damage.
It has been listed as a noxious weed in South Africa prohibited plants that must be controlled. They serve no economic purpose and possess characteristics that are harmful to humans, animals or the environment and in the Australian states of New South Wales. Management The precise management measures adopted for any plant invasion will depend upon factors such as the terrain, the cost and availability of labour, the severity of the infestation and the presence of other invasive species.
Some components of an integrated management approach are introduced below. The best form of invasive species management is prevention. If prevention is no longer possible, it is best to treat the weed infestations when they are small to prevent them from establishing early detection and rapid response. Controlling the weed before it seeds will reduce future problems. Control is generally best applied to the least infested areas before dense infestations are tackled.
Consistent follow-up work is required for sustainable management. Seedlings and saplings can be dug up or pulled up manually but mechanical control of larger plants is very difficult because of their sharp thorns.
Rootstocks will coppice if the roots are not removed or the cut stumps treated with herbicide. Caesalpinia decapetala is sensitive to foliar applications of suitable herbicides but it is very difficult to achieve adequate coverage in dense infestations.
Timely repeat applications every months allows gradual reductions and opening of the canopy and eventual control. Accessible stems may be painted with product suitable product in diesel or crop oil in very-low volume applications basal bark treatment.
When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt consult an expert. A seed feeding insect Sulcobruchus bakeri - Bruchidae have been released in South Africa for biological control of C. A leafmining moth is under evaluation as a possible biological control agent. Legislation Not listed as a noxious weed by the state or governments in Kenya, Tanzania and Uganda. References CABI invasive species compendium online data sheet.
Caesalpinia decapetala Mysore thorn. CABI Publishing Accessed March Dawson, W. Assessing the risks of plant invasions arising from collections in tropical botanical gardens. Biodiversity and Conservation 17 8 : Global Compendium of Weeds.
Hawaiian Ecosystems at Risk Project. GISD Global Invasive Species Database online data sheet. Caesalpinia decapetala shrub , tree. Invasive Species Specialist Group. Henderson, L. Alien weeds and invasive plants. A complete guide to declared weeds and invaders in South Africa. Problem plants in Ngorongoro Conservation Area. Maundu, P. Noad, T. A fully illustrated field guide: Trees of Kenya.
Noad and A. Birnie, Nairobi. Wikipedia contributors. Accessed January
Weeds of Australia - Biosecurity Queensland Edition Fact Sheet
Cultivation This species has been cultivated as an ornamental, and though it is no longer regarded as a useful or popular ornamental species, it may still be occasionally found in old gardens. Naturalised Distribution A relatively widespread species that is mainly found in the coastal regions of eastern Australia. Overseas records of naturalisation include several Pacific Islands i. Habitat A weed of forest margins, disturbed forests, wetter bushland areas, waterways i. Distinguishing Features a large sprawling shrub m tall or tall climber with prickly branches. Seedling The two seed leaves i. All following leaves are usually twice-compound i.
Caesalpinia sepiaria Roxb. Witt pers. It is still being spread in the region as a life fence hedge. The young branches are densely covered with tiny brownish or golden-coloured hairs and have numerous sharp recurved thorns. Older stems are thicker, greyish-brown in colour, and have larger thorns.