Native to tropical and subtropical areas, the Pongam tree, or Pongamia pinnata, was first introduced to Hawaii in the 1860's.  It didn't reach the continental U.S. until 50 years later when the U.S Department of Agriculture was given seeds from Sri Lanka.  The first Pongam tree grown in the U.S. was in Florida in the yard of Dr. David Fairchild.  Over the next 16 years, the USDA received seeds from Mauritius, India, and Egypt.  Although Pongamia pinnata thrives in south Florida, the tree is not very popular because it's excessive shedding of leaves is considered dirty.  It has also been shunned because of its many surface roots.  Today, there are still some Pongam trees growing in Florida and a few other states, but this will never compare to the vast amounts of trees growing in other areas around the world.