Classification
 Nomenclature
Scientific Name:
Xanthium strumarium L.
Synonymy:
  • = Xanthium californicum Greene
  • = Xanthium cavanillesii Schouw
  • = Xanthium chinense Mill.
  • = Xanthium italicum Moretti
  • = Xanthium occidentale Bertol.
  • = Xanthium orientale L.
  • = Xanthium pungens Wallr.
  • = Xanthium sibiricum Patrin ex Widder
Vernacular Name(s):
Burweed; European cocklebur; Noogoora bur; Sheep's bur
 Description

Erect annual, up to c. 1 m tall. Stems sparsely to moderately hairy above, becoming glabrous below, usually branched. Lvs long-petiolate, spineless; lamina green with with scattered short, scabrid, hairs and glands on both surfaces, broad-ovate, irregularly serrate, 3-lobed or not lobed, cordate or truncate at base, 5–15 cm long; uppermost lvs smaller and narrower. ♂ and ♀ capitula in axillary or terminal clusters; ♀ sometimes solitary; ♂ with numerous florets. Fruiting involucre sparsely to moderately scabrid, sometimes almost glabrous at maturity, 15–25 × 8–20 mm; prickles hooked, glabrous or hairy, 3–5 mm long; beaks 2, conspicuous, 4–6 mm long.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]

 Biostatus
Exotic
 Phenology

Flowering: Jan.–Mar.; Fruiting: Mar.–Aug.

 Bibliography
Biosecurity New Zealand 2012: Regional Pest Management Strategies Database. http://www.biosecurityperformance.maf.govt.nz/ [as Xanthium occidentale Bertol.]
Tutin, T.G.; Heywood, V.H.; Burges, N.A.; Moore, D.M.; Valentine, D.H.; Walters, S.M.; Webb, D.A. (ed.) 1964–1993: Flora Europaea. Cambridge University Press.