40 The Science of Life. 



teresting sentences which have a bearing on vege- 

 table morphology, these were only guesses at truth, and 

 Early Antici- must not be taken too seriously. Thus, to 

 pations. quote three examples given by Dr. Masters, 

 Aristotle is reputed to have said, "As a general rule, 

 a plant possesses potentially both root and stem in 

 every part"; Theophrastus said, "Some organs exist 

 only according to analogy, and others, though the 

 same, yet exist in a different manner"; and Nicolas of 

 Damascus ventured the hypothesis that "leaves are 

 properly speaking fruits". But it would be absurd to 

 see in the last sentence, for instance, any prevision 

 of a modern theory, that the vegetative leaf is derived 

 from a sporophyll. There was practically no vegetable 

 morphology until we approach the time of Goethe, who 

 was the first to use the word. 



In this chapter we propose to consider two of the 

 greatest modern morphological achievements in botany 

 the doctrine of metamorphosis, and the recognition of 

 alternation of generations. 



For many years morphological inquiry centred around 



the word metamorphosis, which Goethe defined (1790) 



as "the operation by which one and the 



Metamor- /* 



phosis in same organ assumes various forms . 



Plants""* Unfortunately, however, the word was not 

 always used in the same sense; thus Linnaeus 

 used it quite loosely, sometimes in reference to the 

 changes observed in normal development; sometimes 

 in reference to the observable changes which are seen, 

 for instance, when a wild flower becomes "double" 

 under cultivation; and sometimes in other ways. But 

 the ambiguity of most importance is this: (a) some 

 used the word with definite material content to describe 

 structural changes now observable, or supposed to have 

 been observable in the course of the ages, e.g. the 

 change of a vegetative leaf into a flowering leaf, or 

 vice versa; (b) others used the word with a merely 

 idealistic meaning, being content with convincing them- 

 selves that vegetative leaves and floral parts could be 

 related in thought as metamorphoses of the idea which 

 the supposed "archetypal" plant expressed. 



