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Scientific Name
Synonyms
Family
Common Names
Origin
Naturalised Distribution
Habitat
Habit
Distinguishing Features
Stems and Leaves
Flowers and Fruit
Reproduction and Dispersal
Environmental Impact
Legislation
Management
Similar Species
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Click on images to enlarge

infestation (Photo: Sheldon Navie)

habit (Photo: Sheldon Navie)

habit (Photo: Sheldon Navie)

habit of old plant in fruit (Photo: Sheldon Navie)

leaves with noticeably lobed margins (Photo: Sheldon Navie)

leaf (Photo: Sheldon Navie)

stems with male and female flower-heads (Photo: Sheldon Navie)

close-up of rounded male flower-heads and larger immature fruit (Photo: Sheldon Navie)

clusters of immature fruit (Photo: Sheldon Navie)

mature fruit (Photo: Sheldon Navie)

seedling (Photo: Sheldon Navie)

young plant (Photo: Sheldon Navie)

the very similar Californian burr (Xanthium orientale), with larger fruit and less-lobed leaves (Photo: Forest and Kim Starr, USGS)

Xanthium strumarium

Scientific Name

Xanthium strumarium L.

Synonyms

Xanthium strumarium Bertol.
Xanthium chinense Mill.
Xanthium pungens Wallr.
Xanthium strumarium L.
Xanthium strumarium L. var. glabratum (DC.) Cronq.

Family

Asteraceae (Queensland, New South Wales, the ACT, Victoria, Tasmania, Western Australia and the Northern Territory)
Compositae (South Australia)

Common Names

beach cocklebur, common cocklebur, European cockle bur, European cockle burr, European cocklebur, European cockleburr, large cockle bur, large cocklebur, large cockleburr, Noogoora burr, rough cocklebur, rough cockleburr

Origin

Probably originated in the Americas, but now widespread throughout the world (i.e. cosmopolitan).

Naturalised Distribution

Noogoora burr (Xanthium strumarium) is very widespread, particularly in the eastern half of the country. It is common throughout most of Queensland and New South Wales and is relatively common in some parts of the Northern Territory, northern Victoria and south-eastern South Australia. Scattered populations also occur in the northern and south-western parts of Western Australia.

Habitat

A widespread weed of crops, cultivation, pastures, waterways (i.e. riparian areas), floodplains, roadsides, disturbed sites and waste areas in temperate, semi-arid, sub-tropical and tropical environments.

Habit

This upright (i.e. erect) or spreading short-lived (i.e. annual) herbaceous plant usually grows to about 1 m tall, but occasionally reaches up to 2.5 m in height.

Distinguishing Features

Stems and Leaves

The thick upright (i.e. erect) stems are usually much-branched, giving the plant a spreading habit. These greenish stems often have purplish blotches or streaks and are covered in short, stiff, hairs that give them a rough (i.e. scabrous) texture.

The lower leaves are oppositely arranged, while the upper leaves are alternately arranged. These large and broad leaves (4-20 cm long and 3-18 cm wide) are roughly egg-shaped in outline (i.e. ovate) or somewhat triangular in shape and are borne on stalks (i.e. petioles) 2-12 cm long. They are coarsely toothed (i.e. serrate) and are usually divided into three or five indistinct lobes. The leaves are borne on long, grooved stalks (i.e. petioles) 10-20 cm long and are covered in small hairs or tiny bristles that give them a very rough texture (i.e. they are also scabrous).

Flowers and Fruit

Separate male and female (i.e. unisexual) flower-heads (i.e. capitula) are produced on different parts of the same plant (i.e. plants are monoecious). The male flower-heads (5-8 mm across) are produced in clusters at the tips of the branches, along with a few female flower-heads at the bottom of these clusters. The female flower-heads are also borne in small clusters at the base of the upper leaf forks (i.e. in the upper leaf axils). These greenish or yellowish coloured flower-heads are relatively inconspicuous until the fruit begin to mature. Flowering occurs from summer through to early autumn (sometimes into winter in warmer areas).

The fruit are greenish when young, turning yellowish and then finally brown in colour as they mature. They are oval-shaped (i.e. ellipsoid) 'burrs' containing two seeds. These 'burrs' (7-20 mm long) are shortly-stalked (i.e. sub-sessile) and are borne in groups of 2-13 along the branches. They are somewhat hairy (i.e. pubescent) when young, covered in numerous hooked spines (about 2 mm long), and have two terminal spines or 'beaks' (about 4 mm long). These fruit become quite woody and are usually produced during late summer and autumn. The seeds (4-15 mm long and 5-7 mm wide) are brown or black in colour, flattened on one side, and one seed in each pair is usually slightly larger than the other.

Reproduction and Dispersal

This species reproduces entirely by seed.

The 'burrs' are well adapted for dispersal, due to their hooked spines, and readily become attached to animals, clothing and vehicles. They may also be spread by water, during road maintenance activities, and in contaminated agricultural produce (e.g. particularly in wool).

Environmental Impact

Noogoora burr (Xanthium occidentale) is regarded as an environmental weed in Queensland, the Northern Territory, Western Australia and New South Wales. It was recently listed as a priority environmental weed in seven Natural Resource Management regions.

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

Noogoora burr (Xanthium strumarium) is one of the closely related species that make up the Noogoora burr complex (Xanthium strumarium sp. agg.). The species in this complex can be distinguished by the following differences:

Noogoora burr (Xanthium strumarium) may occasionally also be confused with Bathurst burr (Xanthium spinosum). These species can be distinguished by the following differences: