1. Wildflowers of the Columbia Gorge
by Russ Jolley, Copyright 1988 by the Oregon Historical Society , 1230 S.W. Park Avenue, Portland, Oregon 97205. ISBN 0-87595-188-0
This book is a must for anyone who spends time hiking or biking in the gorge. This is a very complete guide to the wildflowers of the gorge, with more than 700 species represented, each with a small photo, and accompanying information on location and time of viewing. The species are grouped by family. A beginner may have some trouble using this book, but with patience, one can soon identify individual species by looking at the photos. A map of the Columbia River Gorge is included, as well as a monthly listing of what wildflowers are in bloom, and a listing of various sites one may visit and brief descriptions of how to find each site.
2. Survey of Wildflowers & Flowering Shrubs of the Columbia Gorge,
a pamphlet published by the Portland Chapter of the Native Plant Society of Oregon. For those who know their scientific names, this is an indispensible tool for locating and identifying the wildflowers to be found in the Columbia River Gorge. The pamphlet displays most of the known species in the gorge in list form (via family), and gives the elevation range, east-west range, and blooming season.
3. Flora of the Pacific Northwest
By C. Leo Hitchcock and Arthur Cronquist, Copyright 1972 by the University of Washington Press. ISBN 0-295-95273-3
This is the bible of Pacific Northwest Plants, covering the wildflowers, grasses, trees and shrubs of most of the region. It is nicely illustrated with small drawings of most of the thousands of plants identified. However, it would best be used by those familiar with using complex classification keys. An earlier (1961), five volume set, well illustrated with line drawings is also still available. I use both versions of Hitchcock & Cronquist extensively.
4. Northwest Penstemons
By Dee Strickler, Copyright 1997. Published by Flower Press, Columbia Falls, Montana. ISBN 1-56044-572-6.
If you like Penstemons, then you know they're hard to identify. This is a very helpful book, beautifully illustrated with numerous large, color photos, a number of line drawings of key identifying features, and range maps (some of which may be slightly inaccurate). There is also a comprehensive key, which can help get you down not only to the species, but also the variety in many cases. This book has helped me make sense of this beautiful genus of flowers.