INTRODUCTION 



The idea of a bulletin on Michigan trees was first suggested 

 by Prof. Volney M. Spalding. It was thought that a bulletin 

 devoted entirely to the study of certain phases of tree life in 

 Michigan would -.timulate interest in the study of our trees, 

 and influence many more people to associate themselves with the 

 growing number of tree lovers and with the supporters of the 

 movement for better forest conditions in the state. 



The bulletin has been under consideration for a number of 

 years and much of the material given herein has been used in 

 the classes in forest botany at the University of Michigan. It 

 remained, however, for the present Curator of the Botanical 

 Garden and Arboretum to get the material into shape for publi- 

 cation, and the present bulletin is the result of his industry and 

 perseverance. The preparation of the drawings and manuscript 

 has been made by him in connection with his work in the Garden. 



The distinctive feature of the bulletin lies in its keys. The 

 keys commonly published are based upon characters which are 

 present but a short time during the year, or which can be used 

 only by an advanced student of botany. This bulletin presents 

 two-keys. One is based upon characters which are present ail 

 summer; the other uses the winter characters as a basis for 

 identification. By the use of the keys any person should be able 

 to name and learn the characteristics of the trees of Michigan 

 at any time of the year. These keys should prove of special 

 value to our students in the public schools, to members of nature 

 study clubs, and to the students in the forestry schools of the 

 state. 



The order of arrangement and the nomenclature are essen- 

 tially those of "Gray's New Manual of Botany." Following a 

 tendency which is steadily gaining favor, all species names are 

 printed with a small letter, regardless of their origin. For the 

 convenience of the general reader, other scientific names which 

 are found in botanical manuals in common use are printed in 

 v 



