Common name: Stemless Thistle
Onopordum acaulon L. APNI* 
Description: Biennial herb forming a rosette, with a large taproot.
Leaves oblanceolate to elliptic, to 50 cm long, to 12 cm wide, pinnatifid to deeply pinnatisect with triangular lobes, numerous yellow spines to 10 mm long, both surfaces white-tomentose.
Heads solitary or clustered, sessile or on peduncles to 3 cm long in the centre of the rosette, 4–6 cm diam.; involucral bracts lanceolate, 2–3 cm long, acuminately tapered into a straight spine, green, glabrous. Florets white.
Achenes compressed-obovoid, 4–5 mm long; pappus bristles 2–3 cm long, barbellate.
Flowering: October–December
Distribution and occurrence: Weed of irrigated areas, pastures and roadsides, mainly in the Deniliquin-Hay area in the south but also one collection from Walcha. Native of Eur.
NSW subdivisions: *NT, *CWS, *SWS, *NWP, *SWP, *NFWP, *SFWP
Other Australian states: *Vic. *W.A. *S.A.
A declared noxious weed in some shires.
Text by L. Murray
Taxon concept: Flora of NSW 3 (1992)
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.
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