Xanthium occidentale, Fam. Asteraceae
Erect, course annual herb to 2.5m, stems rough to touch, often blotched purple. Previously Xanthium pungens.
Locally Declared Plants
Under the Local Law provision of the Local Government Act 1993, Local Government may declare a weed specifically for their Council area and enforce their control.
|Form or habit:||Herb|
Alternate simple, ovate-triangular, 3-5 lobed, 40-200 x 30-150mm, with irregular coarsely toothed margins, rough textured, prominently veined, dark green above and paler below. Stalk up to 150mm long.
|Flower description:||Greenish inconspicuous, borne in axillary and terminal clusters.|
|Fruit description:||Woody ovoid-oblong brown burrs, 20-30mm long, covered in many hooked spines and terminating in two stout strait spines. Each burr has 2 brown, grey or black seeds contained in separate compartments.|
|Food source for:|
|Toxicity:||Toxic if ingested, toxic to native animals|
|Origin:||Possibly North America & West Indies|
|Notes:||Spread by: burrs attach to ‘everything’ and are moved by water. Invades/threats: river and creek flats, roadsides, old cultivations, pasture land following seasonal rain. Creates impenetrable thicket. Notes: newly germinated seedlings in their two-leaved stage and the burrs are poisonous to grazing animals. As little as 500g of seedling can be fatal to young cattle. Since the 1980’s both rust and the stem galling moth have controlled the spread of Noogoora Burr.|
|Information sources:||Mackay Regional Pest Management Group (2018) Weeds of the Mackay Whitsunday Region Second Edition.|