84 PLANT MORPHOLOGY 



even now difficult to escape, since we can set forth real descent-series 

 only in the fewest instances, and, accordingly, we cannot actually 

 point out the stem-forms. Yet Darwin himself said: 



" We have seen that the members of the same class, independently 

 of their habits of life, resemble each other in the general plan of their 

 organization. This resemblance is often expressed by the term ' unity 

 of type; ' or by saying that the several parts and organs in the differ- 

 ent species of the class are homologous. The whole subject is included 

 under the general term of Morphology. This is one of the most inter- 

 esting departments of natural history, and may almost be said to be 

 its very soul." 1 



The significance of formal morphology cannot be more forcibly 

 expressed than it was by Darwin. And yet we see that, in Germany 

 at least, interest in morphological problems has greatly decreased. 

 Morphological treatises have become relatively less numerous; 

 morphological books, even such excellent ones as, e. g., Eichler's 

 Bluthen-diagramme, do not pass through a second edition, while 

 anatomical and physiological works appear repeatedly in new edi- 

 tions; evidently meeting the demands of the botanical public more 

 fully than morphological works. 2 This may be referred to reasons 

 which lie partly without and partly within morphology itself; .both 

 turn out to be true. Histology, cytology, and experimental physiology 

 have developed remarkably; new methods in this field promise new 

 results; particular lines of work, however, such as descriptive 

 anatomy, are especially favored because the perfection of the methods 

 of research have quite materially lightened the task of working 

 through a vast array of materials, especially for those to whom the 

 other fields of botanical study are more or less unfamiliar. 



But the reasons for the phenomena which lie within the field of 

 morphology are also clear. Some parts of morphology are well worked 

 out, as, e. r/.,the doctrine of the more obvious f orm-relations of plants; 

 and the homologies, at least in the large, are determined, although 

 in the matter of detail much remains vague, and offers a wide field 

 for exhaustive studies in development. More and more, however, 

 these studies bear the stamp of repetition and complement, from 

 which the stimulus of newness is wanting, or they are carried on 

 upon materials which are very difficult to obtain. The constructions 

 of the idealistic morphology, however, often proved to be untenable. 



But the first experiments towards a causal morphology brought 

 disillusion. For only a short time lived the hope of being able to 



1 Origin of Species, ir, 142. 



2 As Eichler wrote me shortly before his death, he would have boon glad to pub- 

 lish a second edition of his work in order to bring to light the numerous thitherto 

 unpublished observations of Al. Braun. The publishers demurred, however, on the 

 ground that there still remained unsold a large number of copies of the first edi- 

 tion. Since then the book has, it seems, gone out of print. Nor to my knowledge 

 has any other morphological work passed through a second edition. 



