PREFACE. 

This little book is prepared with the thought of helping 
young botanists and teachers. Unless the reader has followed 
in detail, by actual experience, some of the modes of plant 
dispersion, he can have little idea of the fascination it affords, 
or the rich rewards in store for patient investigation. 
A brief list of contributions to the subject is given ; but, 
with very few exceptions, the statements here made, unless 
otherwise mentioned in the text, are the results of observations 
by the author* 
I am under obligations for suggestions by my colleague, Prof. 
W. B. Barrows ; my assistant, Prof. C. F. Wheeler ; and a 
former instructor of botany, L. H. Dewey, now of the United 
States Department of Agriculture. B. O. Longyear, instructor 
in botany, with very few exceptions, has made the drawings. 
W. J. Beal. 
Agricultural College, Michigan. 
