I'm pretty good at identifying the plants that grow in my area and I can identify most of the plants that grow on my property in any life stage except for grasses and mosses. This book is the best I've found for identifying grasses. Mosses is another thing altogether.
I have the hardcover 1979 edition. It was very reasonably priced when I bought it a couple of years ago from an internet bookseller. The plants discussed are North American.
The grasses are grouped by visual distinctions rather than by genetic relation which is a big help. In the beginning there is a section that shows you the different features to look at, for example stem shape, and tells you which page to go to as in "If your grass has a triangular stem go to page 42." This helps. I prefer field guides that help you solve mysteries quickly.
Some people prefer photographs to illustrations, but I am satisfied with the lovely illustrations in the book. They have helped me see the subtle differences in grasses that used to look like a jumble to me. Different looking life stages are shown for each grass.
The information is provided simply and concisely. Common name, scientific name, other colloquial names, size, growing habits and other tidbits of interest are included.
Rushes and sedges are covered.
I give it a 9 out of 10
Just put the cards in their christmas stocking and PRESTO! They get it now! It's like you're the harry potter of permaculture. richsoil.com/cards