[Wikipedia] Variety Info: he species has two named varieties.
Astragalus pycnostachyus var. lanosissimus — Ventura marsh milkvetch,[2] now endemic to the Oxnard Plain in Ventura County, with only one population within Oxnard.[3] The single extant population of this rare plant variety is now fenced and protected. The variety is treated as an endangered species on the federal level.[4][3] Threats to its existence include near-total loss of habitat, infestation by weevils, cucumber mosaic virus infection, competition from non-native plants such as ice plant, and herbivory by the milk snail Otala lactea.
Astragalus pycnostachyus var. pycnostachyus — marsh milk vetch, primarily found in the San Francisco Bay Area.[5] (link added by Mary Ann Machi)
Calflora:
Information on California plants for education, research and conservation,
with data contributed by
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[web application]. 2025.The Calflora Database
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https://www.calflora.org/(Accessed: 03/28/2025).