Plants of South Eastern New South Wales
Xanthium occidentale
Common name
Noogoora burr, Cockle burr
Family
Asteraceae
Where found
Low lying areas subject to inundation. Disturbed sites, along streams, river flats, and irrigated ground. Widespread.
Notes
Introduced annual forb to 2 m high. Burrs with many hooked spines, and two longer stout spines at the top. Stems bristly-hairy, purplish. Lower leaves opposite each other, upper leaves leaves alternating up the stems. Leaves 5–16 cm long, 50–160 mm wide, 3- or 5-lobed; cordate to squared off at the base, margins toothed, surfaces rough, more or less dull, 3-veined, the veins purplish, tips pointed. Male and female flowers on the same plant. Individual flower heads small (less than 3 mm in diameter) and inconspicuous. Male flower heads globular, many-flowered, up to 7 at the tops of the stems or at the bases of the upper leaves. Female flower heads many-flowered, oval, in clusters of 1-12, at the bases of the leaves. Female flower heads surrounded by fused bracts completely enclosing the flower heads, the tips of the bracts becoming hooked spines at the seeding stage. Flowers Summer to Autumn. Burrs oval, hairy, 12–20 mm long (including spines).
General Biosecurity Duty all NSW. Pest plant ACT. Noxious weed Vic (as Xanthium strumarium).
PlantNET description: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Xanthium~occidentale (accessed 7 April 2021)
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