PREFATORY NOTE 



The first edition of the Enc(lish translation of this text-book was 

 the work of Dr. H. C. Porter, Assistant Instructor of Botany, 

 University of Pennsylvania. The proofs of this edition were 

 revised by Professor Seward, M.A., F.R.S. The second English 

 edition was based upon Dr. Porter's, translation, which was revised 

 with the fifth German edition. The present edition has been 

 similarly revised throughout with the tenth German edition. 

 Snch extensive cliaiiges, including the substitution of completely 

 new sections on Physiology and Phanerogamia, have however 

 been made in the work since it was first translated, and in the 

 third and fourth English editions, that it seems advisable to give 

 in outline the history of the English translation instead of 

 retaining Dr. Porter's name on the title-page. 



The official plants mentioned under the Natural Orders are 

 those of the P)ritish Pharmacopoeia instead of those official in 

 Germany, Switzerland, and Austria, which are given in the 

 original. In making this alteration I have consulted Materia 

 Medica and Therapeutics, by J. Mitchell Bruce, M.A., LL.D., M.D. 



I am indebted to my friend Mr. D. Thoday, M.A., Lecturer 

 in Plant Physiology in Manchester University, for reading over 

 the proofs of the translation of the section on Physiology. 



WILLIAM H. LANG. 



Manchkstei!. 1912. 



