Ambrosia tenuifolia Spreng.

Lacy Ragweed

Syst. Veg. 3: 851 (1826) APNI

Taxonomic status:Accepted

Occurrence status:Extinct

Establishment means:Introduced

Erect perennial herb to 75 cm high, stoloniferous; stems sparsely branched, with long spreading hairs. Leaves alternate or opposite, rhombic in outline, mostly 2–8 cm long and 4–5 cm wide, bipinnatisect with linear segments mostly less than 1.5 mm wide, surfaces greyish from a covering of long white hairs; petiole to 2 cm long. Inflorescences solitary or few together, 3–7 cm long. Male capitula numerous, 2–4 mm diam., greenish or white; peduncles c. 1 mm long; florets many, slightly exceeding involucral bracts. Female capitula solitary or in small clusters in upper axils; fruiting capitula ovoid, 3–4 mm long, reticulate or slightly ribbed, with 4–6 short spines above, apex with a long central beak. Flowers spring and summer.

Also naturalised WA, SA, NSW. Native to South America. Known only from old collections in the Melbourne metropolitan area at Coode Island, North Melbourne and South Kensington, but most likely occurring elsewhere.

Source: Jeanes, J.A. (1999). Asteraceae. In: Walsh, N.G.; Entwisle, T.J. (eds), Flora of Victoria Vol. 4, Cornaceae to Asteraceae. Inkata Press, Melbourne.
Updated by: Val Stajsic, 2018-03-27
Hero image
Distribution map
life Life
kingdom Plantae
phylum Tracheophyta
superorder Asteranae
order Asterales
family Asteraceae
genus Ambrosia
Higher taxa


Source: AVH (2014). Australia's Virtual Herbarium, Council of Heads of Australasian Herbaria, <>. Find Ambrosia tenuifolia in AVH ; Victorian Biodiversity Atlas, © The State of Victoria, Department of Environment and Primary Industries (published Dec. 2014) Find Ambrosia tenuifolia in Victorian Biodiversity Atlas
  Bioregion Occurrence status Establishment means
Gippsland Plain extinct introduced

State distribution

Distribution map
Western Australia
South Australia
New South Wales