Asclepias cordifolia  Purple milkweed or Heart leafed milkweed is native to northern California the Sierra Nevada mountains  Oregon  and western Nevada. The plant grows in open or shaded woodland  often on rocky slopes and in mixed coniferous forest. The species name  cordifolia (Latin for 'heart-leaved')  refers to the heart-shaped leaves  while the genus name honors the Greek physician Asclepius. It is a larval host to the Monarch butterfly.