THE FERNS 



(FILICALES) 



TREATED COMPARATIVELY WITH A VIEW 

 TO THEIR NATURAL CLASSIFICATION 



VOLUME I 



ANALYTICAL EXAMINATION 

 OF THE CRITERIA OF COMPARISON 



J^ 



BY 



P^^Or^BOWER, Sc.D., LL.D., F.R.S. 



REGIUS PROFESSOR OF BOTANY 

 IN THE UNIVERSITY OF GLASGOW 



CAMBRIDGE 

 AT THE UNIVERSITY PRESS 

 . 1923 



