Shivwits Milkvetch
Astragalus ampullarioides
NatureServe conservation status
Global (G-rank): G1
State (S-rank): S1
Utah Wildlife Action Plan status
- SGCN
External links
General information
Astragalus ampullarioides is a federally listed endangered species known only from Washington County, Utah. This species grows on the unstable clay soils of Chinle Shale in the warm desert shrub and pinyon-juniper communities. Shivwits Milkvetch has many tiny white to cream colored flowers that bloom up tall stems. The leaves are full of many leaflets with a final leaflet terminating at the end giving this plant a very "leafy" powerhouse of photosynthesis at the base.
Description
Astragalus ampullarioides is a federally listed endangered species known only from Washington County, Utah. This species grows on the unstable clay soils of Chinle Shale in the warm desert shrub and pinyon-juniper communities. Shivwits Milkvetch has many tiny white to cream colored flowers that bloom up tall stems. The leaves are full of many leaflets with a final leaflet terminating at the end giving this plant a very "leafy" powerhouse of photosynthesis at the base.
Phenology
Flowers from late April to early June
Diagnostic characteristics
Astragalus ampullarioides is most similar to, and was once treated as a variety of, Astragalus eremiticus. The two can be distinguished by caudex position, stem characteristics, and pod characteristics. A. ampullarioides has a subterranean caudex, hollow stems which often curve upwards, and somewhat inflated pods (8-10 (12) mm thick). Astragalus eremiticus, on the other hand, grows from an above-ground caudex with erect to ascending stems which are not hollow, and produces pods which do not inflate (2.7-8 (10) mm thick).
Species range
Found only in Washington County, Utah.
Threats or limiting factors
Threats include habitat loss due to development, grazing, small mammal herbivory and recreation (USFWS 2021). Some populations are fenced off which excludes recreation and grazing, but the species is very palatable and still threatened by small mammal herbivory (USFWS 2021). Development around some sites may impact pollinator abundance and although this species can self fertilize, seed set is much lower than when cross pollinated (Tepedino 2005). Gene flow between population is also lower than historic levels (Breinholt et al. 2009).
Taxonomy
No, this species does not have taxonomic discrepancies