Southwest Colorado Wildflowers, Astragalus lentiginosus variety palans

The Astragalus genus is large and complex. In Colorado Flora, Western Slope William Weber lists over five dozen species with many sub-species. The new Flora of the Four Corners lists fifty-eight species and several dozen varieties of Astragalus in the Four Corners drainage of the San Juan River. In Intermountain Flora Arthur Cronquist lists 156 species and 122 varieties. World-wide there are about 1600 species.

Astragalus species are difficult to identify and it is the seed pod, not the flower, that is often crucial in the identification process.

The common name, "Locoweed", is applied not to one plant but to many members of the Astragalus genus, for many of these plants absorb toxic soil substances, especially selenium, which cause grazing animals a variety of serious ailments. Further complicating the common name: some people use the name "Locoweed" not only for Astragalus but also for another Pea genus, Oxytropis. And, making common names even more confusing, many Astragalus also carry the common name of "Milk Vetch" (easily confused with other Peas known as "Vetch"). These common names are so confusing that they really should not be used (except in whispers to close friends).

The genus was named by Linnaeus in 1753 and the word "Astragalus" means "ankle bone" in Greek. It is an ancient Greek plant name perhaps given because of the seed shape in some members of the Astragalus genus or, the authors of Intermountain Flora conjecture, because the Greeks used rattling bones for dice and the sound made is similar to the rattling of dry Astragalus seeds in the pod.

Astragalus lentiginosus

variety palans
Fabaceae (Pea Family)

Semi-desert. Openings. Spring.
Canyons of the Ancients National Monument, March 17, 2005.

Beautifully symmetrical, delicately streaked flowers top the mass of leaves on leafless straight stems.

Astragalus lentiginosus

variety palans
Fabaceae (Pea Family)

Semi-desert. Openings. Spring.
Canyons of the Ancients National Monument, May 26, 2011.

Pods are red mottled, gently incurved, and have a distinctive sharply pointed beak.

Astragalus lentiginosus variety palans
Fabaceae (Pea Family)

Semi-desert. Openings. Spring.
Canyons of the Ancients National Monument, May 26, 2011.

Range maps © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Questionable presence

Astragalus lentiginosus

Range map for Astragalus lentiginosus

Astragalus lentiginosus varitety palans

Range map for Astragalus lentiginosus variety palans