6 Introduction 



the idea of evolution had given place to a more sober realization that it 

 did not provide a solution for all the problems about living things. The 

 list of men working primarily with animal material includes some of the 

 most brilliant names in the science of zoology. In plant morphogenesis, 

 most of those who made important early contributions were chiefly en- 

 gaged in other fields, especially morphology, physiology, and pathology. 

 Here are remembered the classical studies of Hanstein on meristems and 

 their derivatives, of Winkler on chimeras, of Haberlandt on plant hor- 

 mones, of Kiister on abnormal growth, of Klebs on the effects of the 

 environment, of Goebel on the general area to which he gave the name 

 of organography, and many others. 



It is to Herman Vochting, however, long Professor of Botany at the 

 University of Bonn, that botanists owe the first thoughtful discussion of 

 such problems as polarity, differentiation, and regeneration. His "Organ- 

 bildung im Pflanzenreich," published in 1878, is a classic and may be 

 said to have founded a new field of botanical investigation. It deserves 

 to be read by all students of development even today. About the turn of 

 the century the zoologist Hans Driesch stated his often-quoted aphorism, 

 "The fate of a cell is a function of its position," which in a few words 

 sums up a central fact of biological organization. What few botanists 

 know is that Vochting, in a book written 20 years earlier, said the same 

 thing in almost the same words. 1 Other botanists also made important 

 contributions here. Much of the work of men such as van Tieghem, Jost, 

 Sachs, Pfeffer, Schwendener, and Strasburger was on problems that we 

 should now call morphogenetic. 



Most studies in plant morphogenesis have been made with vascular 

 plants— pteridophytes, gymnosperms, and angiosperms. It should be 

 remembered, however, that many of these problems can be approached 

 more directly through work on the lower ones. Polarity, for example, is 

 manifest in its simplest form in some of the filamentous algae. The very 

 beginnings of differentiation are to be seen in the lower thallophytes. 

 Almost every cell in some of the bryophytes may easily be induced to 

 regenerate. The problem of the development of form is nowhere posed 

 more directly than in the formation of the remarkable fruiting bodies of 

 some of the myxomycetes and of the higher fungi. These more primitive 

 plants are proving to be ideal material for the study of many problems 

 in physiology and genetics, and although they have been rather neglected 

 in morphogenesis, they offer abundant opportunities for fruitful work 

 in this field. 



The science of plant morphogenesis has never received a comprehen- 



1 Die jeweilig zu verrichtende Function einer Zelle wird in erster Linie durch den 

 morphologischen Ort bestimmt, den sie an der Lebenseinheit einnimmt. Organ- 

 bildung im Pflanzenreich, 1878, p. 241.) 



