Streptanthus polygaloides is a species of flowering plant in the mustard family known by the common name milkwort jewelflower. It is endemic to serpentine soils of the Sierra Nevada foothills of California, where it found in chaparral, grassland, and clearings in oak woodland. It is noteworthy for its ability to hyperaccumlate toxic nickel as an adaptation to living on serpentine soil, while in turn being host plant to the leaf bug Melanotrichus boydi.

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