Plants of South Eastern New South Wales
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Centaurea calcitrapa
Star thistle
Asteraceae
Weed. Woodland, grassy areas, roadsides, wasteland and cultivated areas. Western Slopes, ACT, and tablelands. Occasionally in the Sydney area.
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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