66 Morphology BOOK i 



and sporophylls. We do not find, however, a satisfactory 

 conception of the theoretical or ideal leaf of which all these 

 are modifications. Nor do we find it stated clearly in 

 what direction the modification proceeded whether the 

 order of approximation to the ideal was from foliage leaf 

 to sporophyll, or in the opposite direction, though for 

 purposes of convenience of description, rather than any 

 other, progressive metamorphosis was the term associated 

 with the former, regressive with the latter, change. 



Opinion was not however fixed, for the view of a very 

 definite actual change during development was entertained 

 by many botanists. 



One thing is, however, very clearly seen to have been 

 held as underlying the theory of form. The plant was 

 understood to consist of a few fundamental parts or members 

 which are essentially different from each other, and whose 

 modifications, however interpreted, make up the various 

 forms of plant-body w r hich exist. These fundamental 

 members were held by Wolff to be leaves and stem, the 

 root being included in the latter. The leaf was held to 

 be subject to metamorphosis more freely than the stem. 



The dignity of these parts as morphological members was 

 emphasized in 1867 by Naegeli and Schwendener, 1 who 

 gave to them the names caulome and phyllome, by which 

 they continued to be known till the end of the century. 



At the commencement of our period the clearness of 

 this conception of metamorphosis had begun to be obscured. 

 The wider survey of the vegetable kingdom that had been 

 progressing since the time of Goethe, and which had been 

 prosecuted in the late forties especially by Naegeli, had 

 been directed to a great number of forms of lowlier plants 

 in the construction of whose body the distinction between 

 leaf and stem is not apparent. Naegeli's researches on 

 the Cryptogams had been followed by many other observers, 



1 Das Mikroskop, 1867. 



