Butterfly weed (Asclepias tuberosa)
 
 
Butterfly weed is a member of the Asclepiadaceae or Milkweed family and is also referred to as Pleurisy-root.  It is a perennial plant found June - September in dry, sandy roadsides, and open wood.  Native Americans used the plant medicinally to treat lung inflammation and asthma.


Additional information about this plant may be found at the USDA PLANTS Database:

http://plants.usda.gov/java/profile?symbol=ASTU