Barren Milkvetch

Astragalus cusickii var. sterilis, commonly known as Barren Milkvetch, is a perennial herbaceous plant native to the western United States, particularly found in the regions of Idaho and eastern Oregon. This variety typically grows in dry, rocky soils at elevations ranging from 1,200 to 2,500 meters, often in sagebrush steppe and grassland ecosystems. The growth habit of Barren Milkvetch is characterized by its erect form, reaching heights of approximately 15 to 40 centimeters. The plant often exhibits a bushy appearance due to its multiple stems that arise from a central crown.

The leaves of Astragalus cusickii var. sterilis are pinnately compound, consisting of numerous small leaflets that give a feathery appearance. The leaflets are typically narrow and linear, adapting well to the arid conditions of its native habitat. Flowering occurs from late spring to early summer, with the plant producing clusters of small, tubular flowers that are usually pale yellow to cream in color. These flowers are an important source of nectar for various pollinators, including bees. Following the flowering period, the plant produces elongated, flattened pods containing several seeds, which are dispersed by wind or animal activity.

Ecologically, Barren Milkvetch plays a significant role in its native habitat by contributing to soil stabilization and providing forage for herbivores. The plant is well-adapted to its environment, exhibiting drought resistance through its deep root system that allows it to access moisture from deeper soil layers. Additionally, like many members of the legume family, it has the ability to fix nitrogen in the soil through symbiotic relationships with rhizobia, enhancing soil fertility. This adaptation not only supports its own growth but also benefits surrounding plant communities, making it an integral species in its ecosystem.