Plants of South Eastern New South Wales

Xanthium spinosum

Leaves, female flowers, and young burrs. Australian Plant Image Index, photographer Murray Fagg, near Tarago, NE of Bungendore

Burrs and leaves. Photographer Don Wood, west of Bodalla

Fruiting plant. Photographer Don Wood, Scotia Sanctuary, western NSW

Line drawing in Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. Vol. 3: 344.

Common name

Bathurst burr

Family

Asteraceae

Where found

Woodland, grassy areas, roadsides, disturbed sites, and along streams and flood plains. Widespread.

Notes

Introduced annual herb to 1.2 m tall. Three-branched yellow spines at the bases of the leaves. Burrs hairy, with many hooked spines and two straight spines at the top. Stems sparsely hairy to hairy. Leaves alternating up the stems, 2-10 cm long, 6-30 mm wide, upper surface shiny dark green and more or less hairy, lower surface hairy, margins entire to toothed or 3-5 lobed,  tips pointed. Male and female flowers on the same plant. Individual flower heads tiny (less than 3 mm in diameter). Male flower heads pale green, yellowish, or creamy white, in rounded clusters of 2-8 flowers. Female flower heads yellowish green to brown, usually single. Flowers most of the year.

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=Xanthium~spinosum (accessed 8 February, 2021)