General Introduction 23 



during our period led to the development of a third science, 

 springing very largely from the work of botanists, viz. 

 Cytology, the science of the cell. The cell theory itself 

 may be attributed to the work of a botanist, Schleiden, 

 as much as to that of a zoologist, Schwann ; and its develop- 

 ment fell into the hands of workers in the vegetable as 

 well as the animal kingdom. The direction of research 

 into the peculiarities of the tissues was slightly modified, 

 inquiry being made into their actual structure and 

 composition as well as into their special distribution 

 and relations. As the century drew towards its close 

 a closer alliance was brought about between the anatomists 

 and the physiologists, under the influence of the writings of 

 Schwendener and later of Haberlandt. Another move- 

 ment which arose in Germany under the influence of 

 Radlkofer also calls for mention as a feature of the period. 

 This was the development of research having for its object 

 the elucidation of anatomical relationships between species 

 and genera, with a view to finding therein characters of 

 value for taxonomic purposes. 



When we turn to the field of systematic botany, we find it 

 difficult to trace so clearly the influence of the new current 

 of thought upon the classification of the flowering plants. 

 The period saw, however, a gradual ^withdrawal of the 

 system of de Candolle and his successors. The points of 

 structure on which the larger divisions of this scheme 

 rested became recognized to a certain extent as rather 

 artificial than natural in many respects, and various modi- 

 fications of the system were suggested by more than one 

 botanist. Instead of basing distinctions on the peculia- 

 rities of union or freedom of the floral leaves, and the 

 relative positions of androecium and gynaecium, characters 

 indicating more general affinity came to be more in- 

 sisted upon. This was recognized more especially abroad 

 than in England; in Germany in particular we find 



