TABLE OF CONTENTS 



PART L 

 STATEMENT OF THE WORKING HYPOTHESIS 



CHAPTER HAGR 



INTRODUCTION, - i 



I. THE SCOPE AND LIMITATIONS OF COMPARATIVE MORPHOLOGY, - 5 



II. THE LIFE-HISTORY OF A FERN, 14 



III. ON THE BALANCE OF THE ALTERNATING GENERATIONS OF 



ARCHEGONIATAE, - - 33 



IV. CYTOLOGICAL DISTINCTION OF THE ALTERNATING GENERATIONS 



OF ARCHEGONIATAE, - 46 



V. ALTERNATION IN THALLOPHYTES, - 63 



VI. BIOLOGICAL ASPECT OF ALTERNATION, - 79 



VII. STERILISATION,- 87 



VIII. THE SPORANGIUM DEFINED, - 103 



IX. SOME GENERAL ASPECTS OF THE POLYSPORANGIATE STATE, 113 



X. VARIATIONS IN NUMBER OF SPORANGIA, 119 



XI. THEORY OF THE STROBILUS, - 132 



XII. SPORANGIOPHORES AND SPOROPHYLLS, - 144 



XIII. ON THE RELATIONS BETWEEN THE STERILE AND FERTILE REGIONS 



IN THE SPOROPHYTE, 156 



XIV. EMBRYOLOGY AND THE THEORY OF RECAPITULATION,- 173 

 XV. ANATOMICAL EVIDENCE, - 188 



XVI. SYMMETRY OF THE SPOROPHYTE, - - 201 



