Weed Identification

Australia > > Noogoora Burr

Noogoora Burr

Xanthium occidentale

Alternative Name(s): Xanthium pungens, part of Xanthium strumarium.

Family: Asteraceae.

Form: Herb

Origin: Native of America.

Flowers/Seedhead: Flowers: Unisexual, male and female flowers in separate clusters in upper leaf axils and at ends of branches. Flowers mostly summer and autumn.

Description: Annual herb to 2.5 (rarely to 4) m high. Stems rough to touch with short stout upward directed hairs, green and usually blotched or streaked purple. Leaves dark green above, paler below, covered with small bristles and glandular hairs, margins coarsely toothed, with 3 prominent veins, and with veins and leaf stalks often reddish. Brown burrs each contain two brown, grey or black seeds.

Distinguishing features: Distinguished by spineless stems; ovate or triangular leaves 515 cm long with 3 or 5 lobes, rough to touch; burrs 725 mm long, covered with hooked spines and ending in 2 diverging stout straight spines.

Dispersal: Spread by seed in burrs. Burrs are spread attached to animals, clothing and bags. Burrs float and are moved by water.


Leaves 35 lobed & coarsely toothed

Notes: Noogoora Burr is often abundant after spring or summer floods. Impedes shearing and is a major cause of vegetable fault in wool. Young plants are more toxic than mature plants; sheep, cattle and pigs are affected; poisoning seldom occurs unless stock are starving. Can cause contact dermatitis in humans and animals. Insects and pathogens, some deliberately introduced, damage Noogoora Burr in Australia.

References:

    Noxious Weeds of Australia. W. Parsons and E. Cuthbertson, 1992, pages 313318. The Biology of Australian Weeds. R. Groves et al. (eds), Vol. 1, 1995, pages 241302.

Web References: Search Australian web sites for further information on this weed.


Juvenile

5 species of Xanthium

Forms large bushes

This weed has been included in the WEEDeck field guide as card H24

More information about WEEDeck is available from Sainty & Associates Pty. Ltd.

 

Australia > > Noogoora Burr

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