PREFACE 



This manual offers material for much more than a year's 

 laboratory work. This is made necessary by the fact that in- 

 structors differ widely in their views as to what matter should 

 be presented in an introductory course under the variety of 

 conditions obtaining where botany is taught. • A course must 

 necessarily be framed selectively, and the chief alternatives are 

 discussed in the opening paragraphs of the Introduction. 



The authors fully recognize the fact that no set of directions 

 of only moderate fullness can tell the student all that he needs 

 to know aboult choice of material, apparatus, and manipulation. 

 It is assumed that much is left to be explained by the instructor, 

 and constant mention is made of general and special laboratory 

 guides which may be consulted for needed details. 



The student in the laboratory is not to consider himself as 

 merely the corroborator of facts already ascertained : he is to 

 interrogate mainly not the instructor, not the manual, but the 

 plant itself. The directions here given are, therefore, for the 

 most part suggestions on methods of procedure and indications 

 as to the plants or parts of plants in which to look for desired 

 information. 



Since the amount of ground that can be covered by labora- 

 tory divisions varies so largely with many circumstances, it has 

 seemed desirable to designate two courses, a briefer and a fuller 

 one. The matter which may be omitted from the latter to frame 

 the shorter course is printed in smaller type and consists in the 

 main of rather more difficult or detailed studies than those which 

 appear in the larger type. In a general way the order of treat- 

 ment follows that of the authors' Principles of Botany ^ but the 



