Calotropis gigantea

Crown flower (Calotropis gigantea) is a species of plant.  It is also known as Giant Milkweed.  It belongs in the subfamily Asclepiadodeae.  It is native to southeast Asia.  It has been naturalized in Hawai'i.

Other websites

Calotropis gigantea at USDA PLANTS Database
Calotropis gigantea at Pacific Island Ecosystems at Risk 
Calotropis gigantea at Purdue University: New Crop Resource Online Program

Category:Apocynaceae