iV PREFACE. 



at the same time acquire the habit of close and critical 

 observation, which is indispensable to the successful pros- 

 ecution of natural history studies. To this end the direc- 

 tions for finding the different parts have been made as 

 explicit as possible, and at the same time as little informa- 

 tion given about them as seemed 7 advisable ; for the 

 student having found the part is expected to examine it 

 thoroughly until he has found out all that may be readily 

 seen. This rule has been modified according to the diffi- 

 culties to be overcome, and in extreme cases full information 

 has been provided, which the student is only expected to 

 verify. On the other hand, it will repeatedly happen that 

 more may be learned by an acute observer than there 

 is any hint of in the outlines, as the work, though 

 deemed sufficiently exhaustive for the student, is far from 

 being so for the specialist. 



In the use of such outlines as these there is always 

 danger that the student will slight the study of those parts 

 which he is expected to work out for himself and only 

 attempt to verify the portions where the information is 

 fuller. If it be found that too great dependence is being 

 placed on the manual it will be advisable to substitute 

 plants allied to those named, thus withdrawing all exact 

 information ; the laboratory directions will still serve as a 

 guide to the order and methods of examination. 



It has been no part of the present aim to provide a key 

 to the nomenclature of plant anatomy. When tech- 

 nical terms are used, as indeed is necessarily very frequent, 

 they have usually been preceded by descriptive definitions, 

 either direct or implied. A glossary is added to further 

 assist the student, so that he may find as little difficulty with 

 the names as possible, and devote himself chiefly to the 

 objects themselves. On this account, and on account of the 

 progressive series of forms which have been chosen, it is 



