PREFACE 



TO 



THE AMERICAN EDITION. 



THE translation of the Danish original into 

 German, Italian, and French, and now into Eng- 

 lish, is an honor not dreamed of when the original 

 edition was published. 



I wish to cordially thank all of my collaborators, 

 especially my friends Carl Miiller of Berlin, and 

 Prof. Aser Poli of Melfi, and my honorable col- 

 leagues Dr. Lachmann of Lyon, and Prof. Trelease 

 of Madison, who have not merely enlarged the 

 book, but enriched it with many notes and para- 

 graphs of great value. 



Once more I wish to express the hope that, in 

 the new shape in which it appears, my book may 

 be of use to the students of vegetable histology, 

 for whom it was written. 



V. A. POULSEN. 

 RQSENVAENGETS HOVEDVEJ, COPENHAGEN, June 1883. 



