CONTENTS 



Preface page vii 



Chapter i. Introduction to the Method i 



2. Introduction to the Problem 



3. The Polyploid Series in Osmunda 



4. The Male Fern Dryopteris Filix-mas 



5. The Genus Dryopteris in Britain 



6. The other British Ferns — Polystichuni, Athyrium, Asplenium, Ceterach 



7. The other British Ferns {continued) 



8. Poly podium vulgar e 



9. Three Special Cases of Fern Hybrids : Scolopendrium hybridum, IVoodsia 



10 

 1 1 

 12 



^3 

 14 



16 



17 



and Polystichum illyricum 



Apogamous Ferns. The General Phenomenon 



Apogamous Ferns {continued). Evolution of the Separate Species 



Induced Apogamy 



The Genus Equisetum 



The Psilotales 



The Lycopods (Clubmosses) 



The Ancient Ferns 



Conclusions 



Appendix i. Notes on the Cytological Technique 



2. Notes on the Photographic Technique 



3. General Summary of the Principal New Facts Recorded 



4. Complete List of Chromosome Numbers 



Bibliography 

 Index 



13 

 26 



44 



63 

 88 



1 10 



127 



142 

 158 

 171 

 196 

 209 



233 



244 



262 

 281 



293 

 298 



300 



302 



306 

 311 



65578 



