Field guide to the most common plant species of the Southwest found from 4,500 feet to 11,500 feet, all of which can be found in National Park Service areas. These areas are in Southern Utah, Southern Colorado, Arizona, New Mexico, and a bit of western Texas and Oklahoma. The soils are diverse, as are the climates in which these plants can be found. Here are low mesas, lofty peaks, deep canyons, and shallow arroyos, making up some of the most spectacular scenery in the United States. Each plant includes a detailed drawing of the plant, relative height, foliage, flowers and fruit. The book is also illustrated with color photos of plants and trees in situ.
I like how this book is organized into ecological zones. Yes, the boundaries are blurred, but it's a great starting point. Sitting in the Midwest, I can't really address whether the descriptions are adequate to differentiate similar species, but I would suspect so. This book would benefit from an update. Some of the taxonomy is simply incorrect, and not always do to changes in our taxonomic understanding. In a couple of instances the author says that some species are close relatives when indeed they are not. Also, cultural references are dated. A more contemporary book would use different ethnic terms. I am also skeptical, in this era of widespread foraging, of casual claims regarding edible or medicinal uses. This book is too small to do justice to this topic.
I have probably reference this specific guide in the Southwest Parks and Monuments Association series more than any other. It is organized by ecological belts, e.g. Pinyon-Juniper belt, Pine-Oak belt, Fir-Aspen belt, and Spruce-Fir belt. This is an especially helpful identification guide when exploring the wonderful desert "sky islands" of Southeastern Arizona.