PKEFACE 



THIS book has grown out of a course of lectures, accompanied 

 by laboratory work, given for several successive years. The 

 course presupposes at least a year of work in general morphology, 

 and is intended to prepare the student for research in the mor- 

 phology of Seed-plants. As a consequence, the book brings to- 

 gether and organizes the very voluminous and scattered litera- 

 ture of the subject, points out and discusses the .problems, seeks 

 to unify a very confusing terminology, and at the same time 

 contributes no small amount of original observation and illus- 

 tration. 



In developing the subject it has been thought best to present 

 first the facts connected with the different groups, organizing 

 these facts in as systematic and definite a way as possible, so 

 that the condition of knowledge in reference to any feature may 

 stand out clearly. Following the presentation of the separate 

 great groups, their comparative morphology, history, and phy- 

 logeny are discussed. 



At the end of each chapter which discusses a great group, a 

 list of the works cited is given. This bibliography is not in- 

 tended to be exhaustive, but to include those works which con- 

 tain definite contributions of fact or of opinion. At the close 

 of the volume there will be found a fairly complete bibliography 

 of the important papers. 



While in the very nature of things the great body of ma- 

 terial in a book of this kind must be derived from the work of 

 numerous observers, yet most of the ground has been traversed 



