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 stimulate 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 baesd 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 all 
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 tn common use are printed in 
—Vy— 
