The most popular method of identification is by means of illustrations. In this book will be found illustrations of 1311 species, belonging to 534 genera. As the total number of genera described here is 552 it will be seen that nearly every genus of tree or shrub cultivated in our gardens has been figured. To illustrate every species, amounting to 1732 in all, would have made the book too bulky and expensive. It should not, however, so difficult to name any species, first, by comparing it with the illustrations of others in the same genus, and then by referring to the descriptions given in the later part of the book.
Descriptions of Families and genera have been amplified with the object of bringing to the front the affinities of whole groups of plants. The importance of the Vegetable Kingdom has been stressed by the addition of notes on timber and other economic products.