Oxytropis lambertii

Oxytropis lambertii commonly known as purple locoweed,[1] Colorado locoweed,[2] Lambert's crazy weed,[3] or Lambert’s Locoweed[4] is a species of flowering plant in the legume family.

Oxytropis lambertii
Oxytropis lambertii.jpg
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Genus: Oxytropis
O. lambertii
Binomial name
Oxytropis lambertii


It is native to grasslands in the Canadian Prairie of central Canada and in the mid-west and Great Plains of the United States from Texas to Manitoba and west to Arizona and Montana.[5][1]


Oxytropis lambertii is a perennial herb producing a patch of basal leaves around the root crown, and several showy erect inflorescences. The leaf is compound with several silvery-green leaflets. The inflorescence produces several flowers, each borne in a tubular purple or pinkish calyx of sepals covered thinly in silver hairs. The pealike flower corolla is reddish or bluish purple with a lighter patch at the base of the banner. The fruit is a cylindrical legume pod.


The Oxytropis lambertii plant is one of the locoweeds most frequently implicated in livestock poisoning.[6] The toxin is called swainsonine. Research suggests that the plant itself may not be toxic, but becomes toxic when inhabited by endophytic fungi of the genus Embellisia, which produce swainsonine.[7]

See alsoEdit


  1. ^ a b USDA, NRCS. (2023). "Oxytropis lambertii Pursh". The PLANTS Database. Greensboro, NC USA.: National Plant Data Team. Retrieved 5 January 2023.
  2. ^ Crossley, John. "Oxytropis Lambertii, Purple Locoweed". The American Southwest. Retrieved 5 January 2023.
  3. ^ "Purple locoweed, Lambert's crazy weed". Guide to Poisonous Plants. Colorado State University. Retrieved 5 January 2023.
  4. ^ Fox, III, William E.; Allred, Kelly W.; Roalson, Eric H. "A Guide to the Common Locoweeds and Milkvetches of New Mexico". Cooperative Extension Service (CES) Publications. New Mexico State University. Retrieved 5 January 2023.
  5. ^ USGS. Native Wildflowers of the North Dakota Grasslands
  6. ^ Ralphs, M. H., et al. (2002). Distribution of locoweed toxin swainsonine in populations of Oxytropis lambertii. J Chem Ecol 28:4 701-7.
  7. ^ McLain-Romero, J., et al. (2004). The toxicosis of Embellisia fungi from locoweed (Oxytropis lambertii) is similar to locoweed toxicosis in rats. J Anim Sci 82 2169-74.

External linksEdit

  Media related to Oxytropis lambertii at Wikimedia Commons