Asclepias cordifolia

Asclepias cordifolia (also known as the heart-leaf milkweed or purple milkweed) is a species of milkweed plant. It is not the same as Asclepias purpurascens, which is also known as purple milkweed.  It belongs in the subfamily Asclepiadoideae.  It is native to western North America.  Heart-leaf Milkweed is found in woodlands, rocky slopes, and lava flows.

Other websites

Asclepias cordifolia at USDA PLANTS Database
Asclepias cordifolia at Treatment from the Jepson Manual
Asclepias cordifolia at Plantaxa

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