Weeds of Australia - Fact Sheet

Top Scientific Name Synonyms Family Common Names Origin Cultivation Naturalised Distribution Habitat Habit Distinguishing Features Seedling Stems and Leaves Flowers and Fruit Reproduction and Dispersal Environmental Impact Other Impacts Legislation Management Similar Species

Scientific Name

Senegalia chundra (Roxb. ex Rottler) Maslin

Synonyms

Acacia catechu var. sundra (Roxb.) Kurz

Acacia campylacantha Hochst. ex A. Rich.
Acacia catechu (L. f.) Willd.
Acacia polyacantha Willd.
Acacia sundra (Roxb.) DC.
Mimosa catechu L. f.
Mimosa sundra Roxb.

Family

Fabaceae: sub-family Mimosoideae (New South Wales)
Leguminosae (South Australia)
Mimosaceae (Queensland, the ACT, Victoria, Tasmania, Western Australia and the Northern Territory)

Common Names

black catechu, black cutch, catechu, cutch, cutch tree, dark catechu, gum catechu

Origin

Native to the Indian sub-continent (i.e. India, Pakistan, Bangladesh, Bhutan and Nepal ), southern China, and south-eastern Asia (i.e. Sri Lanka, Myanmar, Malaysia, etc.).

Cultivation

Cutch tree (Senegalia chundra) is generally not grown as an ornamental in Australia. However, it has occasionally been cultivated in botanical gardens in the past.

Naturalised Distribution

This species currently has a very restricted distribution in Australia. Apart from occasional cultivated specimens, it is only known to occur in isolated patches around Darwin, in the Northern Territory.

Habitat

This species is currently only found in areas near habitation in Australia. However, it is considered to be a potential weed of open woodlands, grasslands and overgrazed pastures in tropical, sub-tropical and semi-arid environments.

In India and Myanmar (i.e. Burma), within its native range, it is weedy in overgrazed grasslands.

Habit

A shrub or small tree growing 3 to 15 m tall, but usually only reaching about 6-10 m in height. In cooler climates cutch tree (Senegalia chundra) may lose some or all of its leaves during late winter (i.e. it may be semi-deciduous or deciduous).

Distinguishing Features

• a shrub or small tree with alternately arranged twice-compound leaves.
  
  
• a pair of stout, hooked, spines (5-10 mm long) are usually present near the base of each leaf stalk.
  
  
• its white or pale yellow flowers are borne in dense elongated clusters (35-75 mm long).
  
  
• its large, elongated and flattened, pods (50-125 mm long) have a shortly pointed tip.

Seedling

Seedlings have two undivided seed leaves (i.e. cotyledons). The first true leaves are twice-compound (i.e. bi-pinnate), but only have two pairs of branchlets (i.e. pinnae), each bearing several pairs of tiny leaflets (i.e. pinnules).

Stems and Leaves

The bark on older trees is dark brown to greyish-black in colour, rough, and has numerous lengthwise fissures. This bark sometimes peels off in long strips and the base of the trunk of mature trees can be 30-40 cm across. Younger branches are hairless (i.e. glabrous), or almost so, and have a covering of corky bark. The branches are usually armed with pairs of stout spines (5 to 10 mm long) at the base of each of the alternately arranged leaves. These spines have a broad base and are usually hooked (i.e. slightly recurved), or occasionally straightish.

The leaves (5-20 cm long) are twice-compound (i.e. bipinnate) and have a somewhat ferny appearance. They consist of a leaf stalk (i.e. petiole), which extends into hairy main stalk (i.e. rachis) that bears 7 to 30 pairs of hairy branchlets (i.e. pinnae). The leaf stalk (15-30 mm long) has a small slightly-raised structure (i.e. gland) that is either disc-shaped (i.e. discoid) or oblong in shape. The extension of the leaf stalk (i.e. rachis) is usually 6-12 cm long (sometimes longer) and has similar raised structures (i.e. glands) at the junction of the uppermost one to six pairs of branchlets (i.e. pinnae). These leaf branchlets (usually 3-4 cm long) each bear numerous (6 to 50) pairs of small oblong or elongated leaflets (i.e. pinnules). The leaflets (2-6 mm long) are hairless (i.e. glabrous) or have tiny hairs (i.e. cilia) along their margins.

Flowers and Fruit

The small whitish or pale yellow flowers are fluffy in appearance, with relatively inconspicuous petals and sepals and numerous more obvious stamens. They are stalkless (i.e. sessile) and densely arranged in elongated spike-like clusters (35-75 mm long). These flower clusters are borne on stalks (i.e. peduncles) that emanate from the forks (i.e. axils) of the leaves. There may be one to four of these flower clusters present in each leaf fork. Flowering occurs throughout the year, but is mainly apparent during the wet season (i.e. during late spring and summer in northern Australia).

The fruit is a large and elongated pod (50-125 mm long and 15-20 mm wide) that is borne on a short stalk. These pods are flattened, relatively straight, somewhat shiny in appearance, and have a distinctive pointed tip (i.e. beak). They turn dark brown as they mature and their lower parts are usually softly hairy (i.e. pubescent). When fully mature, they split open to release 2-10 relatively large seeds (5-8 mm across). These seeds are flattened and dark brown in colour.

Reproduction and Dispersal

This species reproduces mainly by seed, although suckering from the base of the plant may also occur. Mature trees can produce large numbers of seeds that are thought to remain viable for many years. Suckering usually only occurs when the main stem is removed, stimulating very dense regrowth from numerous stems.

Seeds may be dispersed large distances after the mature fruit are eaten by larger animals (e.g. cattle). They may also be spread by water, human activities, or in mud sticking to animals, vehicles and footwear.

Environmental Impact

Cutch tree (Senegalia chundra) is on the Alert List for Environmental Weeds, a list of 28 plants that threatren biodiversity and have the potential to seriously degrade Australia's ecosystems. This species can form dense impenetrable stands and has the ability to displace native species in sub-tropical and tropical open woodlands (i.e. savannas) and grasslands. While not currently very widespread, it is seen as a serious threat to such communities in the wet-dry tropical regions of northern Australia.

Other Impacts

In addition to the environmental damage it may cause, cutch tree (Senegalia chundra) also has the potential to cause economic losses to agriculture. Dense stands may significantly reduce the productivity of pastures and its sharp thorns can also impede the movement and mustering of livestock.

Legislation

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

• Northern Territory: A - to be eradicated (throughout all of the Territory), and C - not to be introduced into the Territory.
  
  
• Queensland: Class 1 - introduction into the state is prohibited, and landowners must take reasonable steps to keep land free of this species (throughout the entire state). It is also illegal to sell a declared plant or its seed in this state.

 

• Western Australia: P1 - trade, sale or movement into the state prevented, and P2 - to be eradicated where found (throughout the entire state). Note: All non-indigenous species of Acacia are declared in this state, except mimosa bush (Vachellia farnesiana ).

 

Management

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

• the Northern Territory Department of Natural Resources, Environment and The Arts Agnote on this species, which is available online at http://www.nt.gov.au/weeds.

Similar Species

Cutch tree (Senegalia chundra) may be confused with the mesquites (Prosopis spp.), mimosa bush (Vachellia farnesiana) and prickly acacia (Vachellia nilotica). These species can be distinguished by the following differences:

• cutch tree (Senegalia chundra) usually has a pair of stout thorns (5-10 mm long) near the base of each leaf. Its leaves are twice-compound (i.e. bipinnate) and have numerous (7-24) pairs of branchlets (i.e. pinnae). Its fluffy pale yellow or whitish flowers are borne in elongated clusters (35-75 mm long) in the leaf forks. The large fruit are elongated (50-125 mm long and 15-20 mm wide) and very flattened. These fruit turn dark brown in colour as they mature and have a pointed tip.
  
  
• the mesquites (Prosopis spp.) usually have one or two elongated spines (4-75 mm long) near the base of each leaf. Its leaves are twice-compound (i.e. bipinnate) but they have relatively few (1-5) pairs of branchlets (i.e. pinnae). Their fluffy pale yellow, yellow, greenish-yellow or whitish flowers are borne in elongated clusters (50-140 mm long) in the leaf forks. The large fruit are very elongated (80-200 mm long and 7-15 mm thick) and almost cylindrical. These fruit usually turn yellowish in colour as they mature.
  
  
• mimosa bush (Vachellia farnesiana) has a pair of elongated spines (2-45 mm long) near the base of each leaf. Its leaves are twice-compound (i.e. bipinnate) but they have relatively few (2-4) pairs of branchlets (i.e. pinnae). Its fluffy flowers are bright yellow and borne in small globular clusters (11-15 mm across) in the leaf forks. The large fruit are somewhat elongated (50-70 mm long and 12-20 mm thick) and almost cylindrical. These fruit turn dark brown or black in colour as they mature.
  
  
• prickly acacia (Vachellia nilotica) usually has a pair of elongated spines (2-50 mm long) near the base of each leaf. Its leaves are twice-compound (i.e. bipinnate) and have few to numerous (3-10) pairs of branchlets (i.e. pinnae). Its fluffy flowers are bright yellow and borne in small globular clusters (10-12 mm across) in the leaf forks. The large fruit are very elongated (60-250 mm long and 4-17 mm wide), only somewhat flattened, and strongly constricted between each of the seeds. These fruit turn greyish-green in colour as they mature and are finely hairy.

Cutch tree (Senegalia chundra) may also be confused with several native wattles (Acacia spp.). However, only three species of native wattles have a pair of stout thorns at the base of each leaf (i.e. the native wattles are usually either thornless or have small elongated spines). These three native wattles can be distinguished by their globular flower clusters, as opposed to the elongated flower clusters present on cutch tree (Senegalia chundra).

Note: For a more in-depth key to all of the wattles (Acacia spp.) present in Australia, see the Wattle: Acacias of Australia CD-ROM or Flora of Australia, Volumes 11A and 11B.