This is the definitive guide to wildflowers of the Hill Country. 275 pages and 472 species of plants, each with beautiful pictures of their blooms (where applicable!!).
The photos are consistent (snapped in front of a black background) and are crisp and true-to-color. I've used this to identify plants I find in my own pasture, and, of course, it's great just to sit and read. Each plant is described with its unique characteristics and where it can be found.
This is the best Texas-specific gardening book in my library. I bought my copy in a little store in Fredericksburg.