What an excellent piece of work by Donald Floyd. I am impressed. I only wish he would have added one thing to his narrative on the Welsh "Llwyd." It is a Celtic word and as best we can do in English is to pronounce the word, "thlooid."
Is Mr. Floyd available for contact? I would like to discuss Llywelyn Ap Gruffydd with him. I used a source from Wales several years ago to research the History of Wales. The information he produced states that Llywelyn Ap Gruffydd was never a King, only a Prince. Ap simply means "son of" as there were no Surnames during that period. This person would not have been Llywelyn Gruffydd or Llywelyn Floyd. If the name Gruffydd became Floyd, he would be Llywelyn, son of Floyd. He further stated from Welsh sources that the name Gruffydd became Griffin and not Floyd. The surname Floyd is derived specifically from Llywd (thlooid). Ll has a "sort of" th sound and wy is oo-ee.
Nevertheless, Mr. Floyd has compounded some excellent and most fascinating information. Especially the DNA references. If you are a Floyd Researcher I encourage you to obtain a copy of this book.