Yes, that is it. Warning: it is not for the non-technical plant enthusiast. Make sure you read the reviews before deciding to buy. I first learned plant ID using keys (self taught, who knows how often I actually got it right
). I just like having the combination of the two types of references.
The Turner/Gustafson book does a pretty good job for the hobbyist and I like that they have those maps showing where the plants can be found.