PREFACE. 



IN a compendium of botany intended for high schools it is 

 permissible to introduce subject-matter which would be objec- 

 tionable in a text-book of elementary instruction. Free use has 

 been made of such privileges. It is assumed that the pupil has a 

 general knowledge of chemistry, of physics, of the proper use 

 of scientific terminology, and has the ability to estimate the 

 value of hypotheses and undecided problems. From the con- 

 sideration of the latter the disciple of our science will soon 

 recognize the peculiar difference between layman and scientist. 

 The layman looks upon many phenomena in plant-life as being 

 quite clear and easy of explanation. The scientist, however, 

 can demonstrate that we know but very little concerning these 

 same phenomena. It must also be borne in mind that scientific 

 progress depends upon the recognition of the present limits of 

 our knowledge. 



Nearly every branch of science is more or less merged into 

 general cosmology. It is therefore expected that every scientist 

 should attempt to explain this relation. We find that the vari- 

 ous authors have a tendency to call the reader's attention to the 

 important (in the author's opinion) phases of cosmological rela- 

 tionship. Even of this privilege I have made use. 



Incidentally I will make the following observation : The 

 greater portion of physiology is intimately associated with 

 anatomy. In accordance with this we find that the newer devel- 

 opment of botanic rJ science considers the question, What for ? 

 of prime importance when investigating plant-structures (ana- 

 tomical-physiological tendency of Schwendener's school). 



In the special as well as in the general treatment of the 

 subject-matter I have frequently made use of the works of 

 NAGELI, SACHS, PFEFFEK, DE BARY, FRANK, GOBEL, and WARMING ; 

 more especially those of SCHWENDENER and his pupils (Haber- 

 landt among others). To this I have added the knowledge 



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