The latest issue of Palms has a fascinating article on "Suspected Lesion Mimic Mutants in Mule Palms."  It seems that 20-30% of mule palms probably carry a gene combination that causes the older leaves to whither and die in the sun.  The leaves look like they have a nutrient deficiency or a disease, but it is likely just in their genes.  I bought some seedlings from Mule Palms of Mississippi a while back and some slightly larger ones from another source.  I have been noticing that the leaves on