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Field Guide


Navajo Lake Milkvetch

Navajo Lake Milkvetch (Astragalus limnocharis var. limnocharis)
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Photo by Bill Gray; Bill Gray

Astragalus limnocharis var. limnocharis

NatureServe conservation status

Global (G-rank): G2T2
State (S-rank): S2

Utah Wildlife Action Plan status

  • SGCN

External links


General information

Astragalus limnocharis var. limnocharis is known from Iron and Kane Counties, Utah where it is found on Pink and White Limestone along the shore of Navajo Lake and west of the lake. This species is often associated with western bristlecone pine trees and has an interesting dispersal pattern as it relies on wave action to move the seeds as the water line of Navajo Lake recedes. Navajo Lake Milkvetch is low growing plant with regionally distinct yellow-white flowers and tiny folded leaflets that are hair on the top surface and hairless on the bottom, features that might steal your attention while your are otherwise enjoying the views at Navajo Lake.

Description

Astragalus limnocharis var. limnocharis is known from Iron and Kane Counties, Utah where it is found on Pink and White Limestone along the shore of Navajo Lake and west of the lake. This species is often associated with western bristlecone pine trees and has an interesting dispersal pattern as it relies on wave action to move the seeds as the water line of Navajo Lake recedes. Navajo Lake Milkvetch is low growing plant with regionally distinct yellow-white flowers and tiny folded leaflets that are hair on the top surface and hairless on the bottom, features that might steal your attention while your are otherwise enjoying the views at Navajo Lake.

Phenology

Flowers from July to September.

Diagnostic characteristics

Astragalus limnocharis var. limnocharis is a regionally unique species at Navajo Lake not to be confused with other species there. Astragalus agrophyllus var. panguncensis is another low growing Astragalus that occurs at Navajo Lake.  These species can be positively identified as follows:

Astragalus limnocharis var. limnocharis has white-yellow flowers and folded leaflets that have short stiff appressed hairs on the lower leaf surface, no hairs on top leaf surface and longer hairs on the leaf margins. The fruit are mottled, inflated and hairless.

Astragalus agrophyllus var. panguncensis has purple flowers and silvery hairs covering both sides of the leaves, stems and calyces. The fruit is hairless and not inflated.

Species range

A Southern Plateaus endemic, found in Iron County and Kane County, Utah.

Threats or limiting factors

Threats minimal in most sites (Alexander 2016). One observation noted that trampling was in issue because trail in Cedar Breaks was not well marked and hikers walk all over the hill. Occurrences on the gravel shores at Navajo lake may also be subject to trampling by people while recreating at the lake. Climate change including drought and earlier than normal snow melt may also be impacting this species.

Taxonomy

No, this species does not have taxonomic discrepancies