=Distribution.=--The general distribution of the species is first given, which is followed by the distribution in Indiana. The general distribution has been obtained by freely consulting all the local floras and general works on botany. The Indiana distribution has been obtained for the greater part from specimens represented in the writer's herbarium and from notes in doing field work during the past 24 years. Since the first edition of the "Trees of Indiana" was published the writer has traveled over 27,000 miles in Indiana, via auto, making a special study of the flora of the State, and has visited every county and has traversed practically every township in the State. In discussing numbers in distribution it was decided to use terms already in common use, but to assign a definite meaning to each as follows: Very common means more than 25 trees to the acre; common, 5-25 trees to the acre; frequent 1-5 trees to the acre; infrequent, 1 tree to 2-10 acres; rare, 1 tree to every 11-100 acres; very rare, 1 tree to more than 100 acres; local when the distribution is circumscribed or in spots. Where a species has the limit of its range in our area, its distribution is sometimes given at length for scientific reasons. It should be remembered that some of the older records of distribution were made by geologists or inexperienced botanists, and when such records are questioned it is done with a spirit of scientific accuracy. Some of our early authors did not distinguish between cultivated and native trees, which involves the distribution of certain species. The habitat of many species is discussed; which suggests forestal, horticultural and ornamental possibilities. Then too, the habitat of a tree, helps to identify it. When associated trees are given, those are enumerated which are characteristic of the species throughout its range in our area and they are arranged in the order of their abundance. A county map of the State is included which will assist in finding the range of each species. A forestal area map is also added to visualize certain habitats of the State. The range and distribution of the species in the State has been given considerable attention to encourage investigation along this line. =Remarks.=--Under this title the economic uses of the trees and their products have been given. In addition horticultural and unclassified information is included. =Illustrations.=--All of the illustrations except two are photographic reproductions of specimens in the writer's herbarium. The two drawings were used in the first edition. About 20 of the photographs were made by Paul Ulman, and the remainder by Harry F. Dietz, who has laboriously tried to obtain good reproductions from the material at hand.