As has been discussed above, The Green Man has nothing to do the Foliate Head carvings as found in mediaeval churches, and Lady Raglan's somewhat Frazerian approach to the pagan origins of such folklore further compounds such associations, especially as a lot of pubs called The Green Man now sport stylised Foliate Heads on their signs.

The Green Man as we understand the concept today is essentially a modern construct (in academia no older than 1939, in popular culture circa 1970) based on the above confusions and consequent pagan propagandising.

For more see thread http://www.mudcat.org/thread.cfm?threadid=104331