What a whopper of a text book. Not for the faint of heart, of for those who are only marginally interested in the flora of Utah. This book is huge. It could be used as a weapon! It has been great for learning about plants, though. It's not a field guide so much as a desk reference.
I love how the illustrations in this key often clarify a specific characteristic distinction being made in one of the choices and that they are right there on the same page to assist as you move through the key.