All broadleaved trees belong to the great natural order of plants called the Dicotyledones, which are distinguished by having two seed-leaves or cotyledons in every seed. There are numerous families of these plants, many of which include both trees and smaller plants. Each family is defined, in a rather complicated way, on the basis of the structure of its flowers. A more practical approach is to learn the characters of each genus of trees, with the aid of a book such as this, which brings out their key features. Each plant family is made up of one or more genera, the members of which show a common pattern of bud, leaf, flower, and fruit. Each genus, in turn, consists of one or more species, distinguished by much smaller points of difference. As a handy working plan, the trees described in this booklet have been grouped alphabetically by their generic names, followed, again alphabetically, by the name of each species. The index on the inside back cover gives a quick reference from the English name of each tree.