South Fork John Day milkvetch – State Wildlife Action Plan

South Fork John Day milkvetch

Photo Credit: Oregon Department of Agriculture

South Fork John Day milkvetch is a tap-rooted annual, or possibly short-lived perennial, with several cespitose, spreading, strigose stems 10-40 cm long. Leaves are 3-5 cm long with slender petioles. Leaflets number 9-15, are oblong to obovate, glabrous above and strigose beneath, and 0.5-1.0 cm long. Racemes are short, fewflowered, and are borne on peduncles mostly shorter than the leaves. The calyx is strigose and approximately 0.4 cm long, the subulate teeth equaling or nearly equaling the tube. The corolla is cream or purplish-tinged and 0.5-0.8 cm long. Pods are inflated, ovoid-reniform, finely whitish-strigillose, sessile, 1.5-2.0 cm long and over half as wide. Pods are 1-celled but the lower suture is slightly intruded and forms a thin partial partition.

Overview

  • Species Common Name South Fork John Day milkvetch
  • Species Scientific Name Astragalus diaphanus var. diurnus
  • State Listing Status Threatened

Ecoregions

    Special needs

    This species occurs on barren slopes in stream bottom habitat of the South Fork of the John Day River.

    Limiting factors

    Habitat loss and road construction are major threats to the South Fork John Day milkvetch. Potentially threatened by invasive plants, grazing, changes in historic fire regimes, and off-road vehicle use. Requires adequate winter and spring precipitation for seed production and germination. The species is highly vulnerable to climate change because of limited seed dispersal and predicted changes to hydrologic regimes.

    Data gaps

    Improve understanding of reproductive biology. Develop propagation and transplanting protocols. Document population status and trends.

    Conservation actions

    Develop voluntary conservation projects with private landowners since most sites are privately-owned and habitat has low economic value.