MOSSES, LIVERWORTS, FERNS, LICHENS
  Attempted IDs
MOSSES:  We had difficulty, and were unsuccessful at, finding a beginner/amateur-friendly book with color pictures to go along with scientific descriptions.  Wanting to learn to identify some of the common mosses we signed up at Hawk Mountain for a walk with Susan Munch.  We were pleased to find she had a book available that suited our very amateur status: "Oustanding MOSSES & LIVERWORTS of Pennsylvania & Nearby States", by Susan Munch. The book can be ordered by e-mail at susanm@alb.edu.
LICHENS:  http://www.fs.fed.us/wildflowers/beauty/lichens/importance.shtml 
see also: http://www.easttennesseewildflowers.com/gallery/index.php/lichens
There are 6 types of lichens:  Crustose - crusty, Foliose -leafy, Fruticose - long-hairy, Squamulose - scaly shelf-like, Umbilicate, on rocks w/"umbilical" cord, Gelatinous - jelly-like