I've read several hypothesis of the names origin. I know through part of my family oral history it was said Jarman came to America from Wales. Jarman's still reside in Wales. Another report says Jarman is an English name, but to the best of my knowledge some Jarman's migrated to England from Wales, hence many assumed the name originated in England. Many Welsh would not appreciate anyone calling them English. At the least they would settle for being called British. Another says the name is derived from German, and was originally from the European continent. Maybe the name German was a derivation of Jarman. I have found in my lifetime many have trouble with the spelling of the name, and want to spell it German, or Jerman, or even Jordan. Another is that the name derives from the St. Germain area of Alsace-Lorraine[between France and Germany]. Take your pick among these. As a final confusion surnames did not exist in Wales until the sixteenth century or later. A son was named the son of such and such, as in William, ap John.