These one inch wide nodules were present on some of what I thought were queen palm roots, which I encountered while I was digging  up some of the southwest garden.   I have been unable to find anything online to explain what they are.  Are they bacteria harboring nodules to fix nitrogen?  Sooner or later I will find out what they are.

Here are the queen palms, photographed in December 2013.

As you see, I dug around the queen palm bases in order to be able to plant the vegetables and flowers that I most recently planted, and in doing so, I disturbed the roots to some extent.  this is how I found those roots with nodules.