DERIVED AND METAMORPHOSED FORMS. 7. 



whereas the systematic or phylogenetic mode of consideration leads us to the 

 conclusion, that the flower shoots are to be considered as altered leaf shoots, of 

 which the capacity for assimilation has ceased, because they take part in the function 

 of fertilisation. They are in this sense, therefore, reduced forms of shoot. In the same 

 way, we may assume that the tendrils of the Vine, in spite of their containing 

 chlorophyll, yet scarcely come into consideration in the assimilation of the whole plant ; 

 whilst they serve it as climbing organs, and in so 'far contribute to the green 

 leaves being able vigorously to carry on their function of assimilation. Again, we 

 may regard the numerous subterranean forms of shoot as derived from green leafy 

 shoots, which, however, on their part, assist in the performance of the processes of 

 nutrition by the latter in this or that manner. It is against common sense to regard 

 those kinds of organic forms, which have it is true only been derived later from the 

 typical ones but which contribute to the greater perfection of the entire organism, 

 simply as degenerations. In order to express this objection adequately in language, 

 I shall designate these kinds of organs, derived or metamoiphosed forms ; a flower, 

 a vine-tendril, a subterranean runner, &c. are thus, for us, derived or metamorphosed, 

 shoots ; and in the same way, roots which serve the function of nutrition either not 

 exclusively or not at all, but rather do duty as climbing organs, reservoirs of reserve 

 material, and so forth, are not necessarily to be termed reduced, but more generally 

 as derived or metamorphosed forms of root. 



In this setting forth of the ideas of rudimentary, typical, derived and reduced 

 organs, we also find at once the reason why it is in general quite impossible to 

 characterise correctly by means of short, precise definitions, a comprehensive category 

 of organs : thus, in comparison with the typical forms of a group, various characters 

 may yet be wanting to the rudimentary forms of the same group ; on the other hand, 

 certain characters may become lost by degeneration, and it is obvious how very 

 difficult it is, under such circumstances, to have regard to all these various cases in 

 a definition. 



It is therefore, in my opinion, the best, as well for research as for my exposition, 

 .to find out first by careful comparison of very many cases, what organic forms present 

 themselves as typical within a categorj^ these are precisely those organs where the 

 forms concerned are developed in the highest degree : one has then only yet to 

 establish, whether and how far other forms are to be looked upon as rudimentary 

 or derived. The setting up of a tjrpical form supphes in a certain manner the ideal 

 towards which the rudimentary forms are striving, and from which the derived forms 

 have fallen away again ^. 



' The usual division of all organs of the plant into root, stem, and leaf, no longer comes 

 up to the present state of science — at best it might hold good exclusively of the vegetative organs. 

 Nevertheless, it will, as I believe, clearly result from v^hat has already been said in the text, as well 

 as from the following lectures, that there is no meaning in considering stem and leaves separately 

 from one another, as two groups co-ordinated with the roots ; that, rather, both together are to 

 be co-ordinated with the root, as shoot. Since what is necessary has been said in the text, it is 

 superfluous to attempt any further demonstration here. 



Yet a few words in anticipation on the reproductive organs, to which I shall, however, return 

 in the last part of this book. That the reproductive organs in the first place of the phanerogams 

 were regarded as leaves, or as appendages of such, in the sense of the doctrine of metamorphosis, 

 was only justified so long as the stamens and carpels of the phanerogams were considered as the 

 true sexual organs. No attempt was made to arrange the arcliegonia and antheridia under one of 



