I think that there is really a void when it comes to bryophyte field guides for amateurs. I have sent emails to both the Peterson's Field Guide company and the Finder guides suggesting that a guide to the moss genera of North America is desperately needed. Unfortunately there was no reply from either company. I guess they don't think that there is a market for this type of guide. I think that there is, considering that I am asked about what field guide I would recommend quite often.
The first guide that I purchased was Conrad and Redfearn's "How to know the mosses and liverworts". This guide is ok, but the dichotomous key at the beginning is really long and painful. You have to really want to learn about mosses to pull the information that you desire out of this book. Also some of the characteristics they have you look for are microscopic and really cannot be seen with a 10X handlens.
An announcement came out on Bryonet a while back about a new bryophyte guide. It is entitled "A Trailside Guide to Mosses and Liverworts of the Cherokee National Forest" by Paul G. Davison with contributions from Mark J. Pistrang. If you have never visited the Cherokee National Forest, it is a fabulous place. I carried out some of my undergraduate research there and participated in the All Taxa Biodiversity Inventory in the Smoky Mountains. Fortunately many of the genera in this area overlap with other eastern deciduous forest regions of the United States, and thus could be used outside of the region.
I have purchased a copy and I think that this book is great. There are multiple color photographs per genus. The text includes a description about the genus; notes on habitat, size, distinguishing characteristics and reproduction; the number of species in the genus that live in the Southern Appalachian Mountains; the distribution of the genus within Eastern North America. The book covers 52 genera and focuses on larger scale photographs. Thus a microscope is not needed, which is critical for making field identifications.
The specific species that are covered may not be found in your area, but I think that identifications of mosses and liverworts to genus are just fine. When I lead moss walks and teach people local plants we only talk about them in terms of the genus identification. Really to identify these plants to species you need a microscope. However there are a lot of genera to be learned with ~12,000 different moss species worldwide.
9 minutes ago in Catalogue of Organisms