This is the best guide that I have found for identifying western plants. Includes color photographs plus notes on habitat and range; edibility; medicinal uses; and look-alike plants.
"This book is an indispensable basic manual for the real-life issues that await us in the decades to come. Those who read it, and pay attention to its treasure trove of practical wisdom, will enjoy a huge advantage as the cheap oil fiesta winds down and circumstances compel us to live differently."