vui CONTENTS 



PAGE 



Chapter III. Cycadales • 91 



1. Vegetative organs 93 



Vascular anatomy 93 



Leaf 108 



Root . . 112 



2. Spore-producing members 114 



Microsporangium 114 



Megasporangium 121 



3. Gametophytes 132 



Female gametophyte 132 



Male gametophyte 139 



Fertilization . ........ 148 



4. Embryo 150 



5. History and distribution 156 



6. Relationship to other gymnosperms . . . . 157 

 Literature cited 158 



Chapter IV. Cordaitales 163 



1. Vegetative organs 164 



Vascular anatomy 165 



Leaf 168 



Root ... 171 



2. Spore-producing members 172 



Strobilus 172 



Microsporangium 172 



Megasporangium 174 



3. Gametophytes 178 



4. History and distribution . . . 180 



5. Relationship to other gymnosperms 180 



Literature dted .... .... 183 



Chapter V. Ginkgoales 185 



I. Vegetative organs 185 



Vascular anatomy 187 



Leaf 189 



