From Barbara’s link:
What good is a field guide that relies upon . . . minute differences in leaf shape when a flower is seen from a car traveling 70 miles per hour? [112 km per hour]
The world desperately needs a guide that . . . identifies characteristics of wildflowers as most people actually experience them. This is that guide.
When I had a class on tree and shrub ID, the instructor said, “You will train on these IDs until you can do them drunk, from a car, as you’re speeding down the highway!”