PREFACE • 



The papers contained in this voUime were presented on April 20- 

 21, 1917, either in person or by title, at the Scientific Program, which 

 formed part of the Dedication Exercises on the occasion of the com- 

 pletion of the Laboratory Building and Plant Houses of the Brook- 

 lyn Botanic Garden. 



Orland E. White, 

 Edgar W. Olive, 

 Alfred Gundersen, 

 Publication Committee 



