Ambrosia acanthicarpa
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Genus: Ambrosia
A. acanthicarpa
Binomial name
Ambrosia acanthicarpa
  • Franseria acanthicarpa (Hook.) Coville
  • Franseria californica Gand.
  • Franseria hookeriana Nutt.
  • Franseria montana Nutt.
  • Franseria palmeri Rydb.
  • Gaertneria acanthicarpa (Hook.) Britton
  • Gaertneria hookeriana (Nutt.) Kuntze

Ambrosia acanthicarpa is a North American species of bristly annual plants in the sunflower family. Members of the genus Ambrosia are called ragweeds. The species has common names including flatspine bur ragweed,[2]Hooker's bur-ragweed,[3]annual burrweed, annual bur-sage, and western sand-bur. The plant is common across much of the western United States and in the Prairie Provinces of Canada.[4][5]

This spiny, weedy plant grows in clumps of many erect stems which may reach over a meter in height. Its gray-green stems are covered in a coat of stiff, bristly hairs. The few rough leaves are several centimeters long. The racemes of flowers are more plentiful, with each hairy flower head a few millimeters wide. The spiny, burr-like pistillate heads have pointed, twisting bracts and the staminate heads are rounded. The species is adaptable and grows well in disturbed areas, easily becoming weedy.[6]


  1. ^ The Plant List Ambrosia acanthicarpa Hook.
  2. ^ "Ambrosia acanthicarpa". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 8 January 2016.
  3. ^ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
  4. ^ Biota of North America Program 2013 county distribution map
  5. ^ Great Plains Flora Association. 1986. Flora of the Great Plains i–vii, 1–1392. University Press of Kansas, Lawrence.
  6. ^ Flora of North America Vol. 21 Page 15 Ambrosia acanthicarpa Hooker, Fl. Bor.-Amer. 1: 309. 1833.

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