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U.S. Forest Service

Plant of the Week

Map of the United States showing states. States are colored green where the species may be found. Astragalus musiniensis range map. USDA PLANTS Database.

Astragalus musiniensis. A botanical jewel of the Colorado Plateau, the lovely Ferron's milkvetch (Astragalus musiniensis) is not easily forgotten. Photo by Teresa Prendusi.

Habitat for Astragalus musiniensis. Habitat for Ferron's milkvetch can be found in open Pinyon-Juniper woodlands in central Utah's red rock country. Photo by James Stone.

Ferron's Milkvetch (Astragalus musiniensis)  M.E. Jones

By Teresa Prendusi

With over 18,000 species, the legume family (Fabaceae) is the third largest flowering plant family on earth and second only to the grasses in terms of economic importance. Many familiar foods on our dinner table are members of the legume family including: all varieties of beans and peas, peanuts, soybeans, and carob, to name a few. Valuable forage species such as the alfalfas and various clovers form the backbone of the meat, dairy and rangeland management industry, infusing more that 5 billion dollars annually into the US economy.

The genus Astragalus is the largest vascular plant genus on earth with over 3,000 species worldwide and an important member of the Fabaceae. At least 500 species, subspecies and varieties of Astragalus are found in North America, most commonly in semi-desert areas, prairies and Pinyon-Juniper woodlands. The Great Basin is a center of Astragalus biodiversity and endemism, with over 156 taxa occurring within the intermountain region.

Utah, in particular, is especially rich in endemic Astragalus species. One such beauty is Ferron's milkvetch (Astragalus musiniensis). Finding this lovely pink-flowered milkvetch among the open, mixed desert scrub and Pinyon-juniper vegetation in early springtime is a rare treat. It is a perennial, acaulescent (stemless) plant about 3 to 13 centimeters. tall. Its pinnate leaves are up to 13 centimeters long, each leaf bearing 1 to 5 stiff-haired (strigose) leaflets. The striking flowers are 20 to 28 millimeters long, which in a year of good rains can overwhelm the entire plant in size and beauty. Ferron's milkvetch is endemic to the east-central portion of Utah’s Colorado Plateau and adjacent western edge of Colorado. Its preferred habitat is fine-textured substrates, mostly on broken sandstone or shale at an elevation of 1,430 to 2,320 meters. Marcus E. Jones first found and described this species in 1913. Jones was a colorful mining engineer turned botanist. It was said that he “had a tendency to offend everyone he came in contact with.” Jones established a small botanical journal, “Contributions to Western Botany,” as a protest to the Eastern establishment’s stranglehold on publishing new botanical names and taxonomic literature.

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