Introduction < 



sive formulation. To bring together in a single volume a discussion of 

 the various phenomena that distinguish it and of the factors that have 

 been found to affect the development of plants, together with a bibliog- 

 raphy of some of the most important publications dealing with the sub- 

 ject, should help to give it recognition as a distinctive botanical disci- 

 pline. To attempt this is the purpose of the present volume. 



Morphogenesis is such an immense subject, however, covering most of 

 the territory of biology, that to organize its facts and its problems in a 

 logical and reasonably compact fashion is a matter of much difficulty. 

 The method used here is to divide the subject into three parts. First is 

 presented a brief discussion of plant growth as a necessary introduction 

 to morphogenesis proper, placing particular emphasis on its cellular basis 

 and on the activities of the meristems. The remaining subject matter is 

 then divided into two sections: first, the various phenomena of plant 

 morphogenesis and the more important studies that have been made on 

 them and, second, a brief account of the morphogenetic factors that have 

 been found to affect the development and form of plants. In the first 

 there are chapters on Correlation, Polarity, Symmetry, Differentiation, 

 Regeneration, Tissue Mixtures, and Abnormal Growth. In the second are 

 discussed the effects of light, water, temperature, and other physical fac- 

 tors; inorganic and organic substances (especially growth substances); 

 and finally the various genetic factors. There is a concluding chapter on 

 the problem of Biological Organization. 



At the end of the book is a selected list of references to some of the 

 more important books and papers on the subject. This obviously must be 

 far from complete since the literature is enormous and scattered through 

 most of the fields of botany. An attempt has been made to include, both 

 in text and references, some of the important early work, not alone for 

 its intrinsic but also its historical value. In the more rapidly advancing 

 fields, where many of the results from older studies have now been 

 superseded, only a relatively few of the earlier papers are mentioned, 

 and there is considerable representation of recent work. Aside from 

 bringing the subject up to date, these later papers through their 

 bibliographies will give the student a means of entry into the literature 

 of a given field. Opportunities for further research, particularly in areas 

 now less popular than in the past, are so numerous that the author has 

 felt justified in calling attention to some of them from time to time. 



The problem of deciding which pieces of work to include in a discus- 

 sion of this sort and which to omit has been very difficult. Among those 

 mentioned there are doubtless some that will be regarded by many read- 

 ers as relatively unimportant. The omission of others will be criticized. 

 It is hoped, however, that the papers chosen will provide a fair picture of 

 accomplishment in plant morphogenesis. A considerable number of 



