Mike:
Reindeer Moss is the tight, subtle tuffs of lichen. It is great when it's scenic-bashed. Take the tuffs and spray hair spray or spray adhesive on them and roll them around in WS ground foam of various colors and you have small tress and brush. I once picked several trash bags of this growth from a state park in Missouri and cooked it up with liquid glycerin to preserve it and died it green with dye. Then rolled it around in ground foliage and it looks great. The only problem with lichen without the foliage/foam is it looks like toy trains layouts of the 70's.