=Botanic Description.=--The botanic descriptions have been made from specimens collected in Indiana. In most instances the material has been quite ample, and collected from all parts of the State. Technical terms have been avoided, and only when precision and accuracy were necessary have a few been used which can be found in any school dictionary. The length of the description varies in proportion to the importance and interest of the species and the number of characters necessary to separate it from other forms. The characters used are those which are the most conspicuous, and are generally with the specimen at hand. In most instances mature leaves are at hand, and these are most fully described. When leaves are discussed, only mature and normal leaves are considered. The descriptions are not drawn to include the leaf forms, and sizes of coppice shoots or seedlings. Measurements of simple leaves do not include the petiole unless mentioned. When the term twig is used, it means the growth of the year. Branchlets and branches mean all growth except the present year. By seasons are meant the calendar seasons. The size of trees is designated as small, medium and large. These terms are defined as follows: Small trees are those that attain a diameter of 2 dm.; medium-sized trees are those whose maximum diameter is between 2 dm. and 6 dm.; large-sized trees are those which are commonly more than 6 dm. in diameter. Diameter measurements are at 14 dm. (4-1/2) feet above the ground, or breast high. The common names given are those most generally used in our area. Where common names are rarely applied to our forms, the common commercial or botanical common name is given. In some instances where a tree is known by several names, one or more of which are often applied to a related species, the liberty has been taken to select a common name which should be restricted to the one species. Botanical names are usually pronounced according to the English method of pronouncing Latin. The accented syllables have been marked as follows: the grave (\) accent to indicate the long English sound of the vowel and the acute (/) accent to show the short or otherwise modified sound. Measurements have been given in the metric system, and in some instances the English equivalent has also been given. The nomenclature attempted is that of the International Code. The sequence of families is that of Gray's Manual, 7th Edition.