The character we now call the Green Man dates back over 2,000 years and is as varied in representation as it is in number. The variations can be broken down into three main categories.
The Foliate Face - this variety of Green Man has a face made entirely of leaves and is the oldest variety. Sometimes it looks like a mask, other times it looks like a plant with the face of a man. These Green Men are usually serious, sometimes brooding and somber, other times wise and dignified.
The Sprouting Face – this variety has leaves, branches and vines sprout out of the mouth, nose, ears and sometimes eyes. The oldest dates from the 5th century in France. It’s the sprouting variety that are the most common because most Green Men are found in medieval churches in Britain, France and Germany, from the 12th to the 15th century, and during that time the sprouting Green Man was the preferred variety.
The Other Kind – The third variety, as far as I can tell, doesn’t have a name. It is simply not a foliate face or a sprouting face. This variety of Green Man has a man's face but his hair, eyebrows, moustache, and/or beard is made of leaves.
Jack of the Green - Sometimes people confuse this ancient character with the more recent Jack of the Green or Jack of the Wood. The confusion stems from his naming. In 1939, Lady Raglan was writing an article on these foliate faced carvings that show up over and over in medieval cathedrals. They reminded her of the costumed wild man who parades around on May Day in a costume of leaves in England. He is called the Jack-of-the-Green, so she called them ‘Green Men’.
Most scholars today find it unlikely that this fun-loving character is the same as the one depicted with the grotesque vine- sprouting face or venerable foliated face that adorns medieval cathedrals. One reason for this is that this shaggy Wild Man character already existed in medieval times and he was quite different in his representation. Here he is in medieval illuminated manuscripts.