Plants of South Eastern New South Wales
Onopordum acanthium
Common name
Scotch thistle, Heraldic thistle
Family
Asteraceae
Where found
Grassy areas, disturbed sites, and roadsides. Western Slopes, ACT, and tablelands. Occasional elsewhere.
Notes
Introduced annual or biennial herb to 2 m tall. Stems, leaf margins, and bases of the flowers spiny. Stems whitish-grey, hairy, with broad spiny wings. Leaves forming a rosette in the first year, 10-40 cm long, 30-100 mm wide, then alternating up the stems, becoming smaller and narrower, bases continuing down the stems, margins toothed or deeply divided with numerous robust spines to 10 mm long, upper surface grey-green and sparsely woolly, lower surface paler and more densely woolly. Flower heads green, 20-60 mm long, 35-50 mm wide, almost globular, with many purple, reddish purple, or mauve florets. Flower heads in clusters of 1-3 flower heads. Bracts surrounding the flower heads less than 3 mm broad at the base, yellow, and only the outer bracts are bent sharply down. Flowers Winter to Summer.
Onopordum acanthium subsp. acanthium in PlantNET.
Hybridises with Onoporum illyricum.
General Biosecurity Duty all NSW. Pest plant ACT. Noxious weed Vic.
PlantNET description: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=in&name=Onopordum~acanthium~subsp.+acanthium (accessed 13 April 2021)
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