Plants of South Eastern New South Wales
Centaurea calcitrapa
Common name
Star thistle
Family
Asteraceae
Where found
Weed. Woodland, grassy areas, roadsides, wasteland and cultivated areas. Western Slopes, ACT, and tablelands. Occasionally in the Sydney area.
Notes
Introduced annual or biennial herb to 1 m high. Bracts on the flower heads spiny. Stems much-branched, grooved; stems and leaves with coarse hairs. Basal leaves short-lived, to 20 cm long, to 50 mm wide, deeply dissected, the margins of the lobes toothed. Stem leaves alternating up the stems, the lower stem leaves lobed, to 2–8 cm long, 10–30 mm wide, dark green; upper leaves entire, 2–4 mm wide, becoming linear. Flower heads 10-15 mm long below the 'petals', 6–10 mm in diameter, oval to cylindrical. Florets ('petals') pale purple, pink, or white, 15–20 mm long. Flower heads single. Flowering: spring–summer.
General Biosecurity Duty all NSW. Noxious weed Vic.
PlantNET description: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Centaurea~calcitrapa
(accessed 7 January, 2021)
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