Selected Plants of Navajo Rangelands

Take care of our Navajo Rangelands

Loco, rattleweed
(a.k.a. rattleweed, Half-moon milkvetch)

Pink, slightly tubular, pea-like flowers with foliage

Rattleweed loco is native to Texas, New Mexico, and Arizona. This plant contains swainsonine, which is toxic to livestock.

To recognize it in the field, look for green leaves; small, bluish or purplish flowers; pods that are inflated and bladderlike; and sparse hairs near the base of the plant.

The plants are usually annual, sometimes persisting into a second season, with several stems 4 to 20 inches tall.

Locoweed species on the Navajo Nation may include:

  • Astragalus amphioxys
  • Astragalus beathii (Group 4, Navajo Endangered Species List)
  • Astragalus ceramicus E. Sheldon var ceramicus
  • Astragalus cronquistii (Group 3, Navajo Endangered Species List)
  • Astragalus cutleri (Group 2, Navajo Endangered Species List)
  • Astragalus heilii (Group 4, Navajo Endangered Species List)
  • Astragalus humillimus (Group 2, Navajo Endangered Species List)
  • Astragalus humistratus
  • Oxytropis lambertii
  • Astragalus lentiginosus Douglas ex Hooker var australis Barnely
  • Astragalus lonchocarpus
  • Astragalus missouriensis
  • Astragalus mollisium
  • Astragalus naturitensis (Group 3, Navajo Endangered Species List)
  • Astragalus nuttallianus
  • Astragalus praelongus Sheldon var ellisiae

Bladder-shaped pods and foliage displaying the slightly sprawling growth habit of the plant
A plant in transition with some pink flowers remaining but with bladder pods also formed
Growth habit showing several stems and the leaflets, which are not tremendously dense in their arrangement

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