Plants of South Eastern New South Wales

Onopordum illyricum

Flower head and leaves. Australian Plant Image Index, photographers RG and FJ Richardson, south of Young

Flowering plant. Australian Plant Image Index, photographers RG and FJ Richardson, south of Young

Line drawings. e. flowering branch; flower head; bracts; floret and seed. E Beckett, University of Oxford, © 2021 Royal Botanic Gardens Board

Common name

Illyrian thistle

Family

Asteraceae

Where found

Weed of pastures, grassland, roadsides, disturbed sites, and wasteland. Widespread. No records from the ranges.

Notes

Introduced annual or biennial herb to 2 m high. Spiny stems, leaves, and bases of the flowers. Stems white woolly, with continuous spiny wings 3–10 mm wide. It forms a rosette in the first year and then develops an erect flowering stem. Basal leaves to 55 cm long, to 150 mm wide, stalked, deeply dissected, with numerous spines 4–10 mm long, surfaces white- or grey-tomentose. Stem leaves alternating up the stems, bases continuing down the stems. Flower heads 30–60 mm in diameter, with many purple florets ('petals'). The bracts surrounding the flower head to 3 cm long, much broader than 3 mm at the base, reddish-purple, and protruding slightly more from the head than the flower head of Onopordum acanthium. Flower heads few, in open clusters at the tops of the stems, often appearing single. Flowering: December–February.

Onopordum illyricum subsp. illyricum in PlantNET.

Hybridises with Onoporum acanthium.

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=sp&name=Onopordum~illyricum   (accessed 13 April 2021)