What Does Milkweed Look Like?

I have been asked by several people to verify milkweed.  There is at least one local plant that mimics a milkweed plant.  It's known as "false" milkweed and has single white flowers instead of the clusters found on milkweed.  There is a white flowering swamp milkweed so be careful!  Both of these plants do spill a milky sap when broken.  When in doubt, look for the purple flowers in a cluster at the top. The plant below is NOT a milkweed that will nourish a monarch caterpillar.  It is actually toxic to them.

 This is what its flowers look like.  DO NOT feed this plant to your monarch caterpillars!