Vii CONTENTS. 



VII. 



PACK 



GERMINATION AND GROWTH 137 



VIII. 

 SEXUAL REPRODUCTION . . 163 



IX. 



POLYMORPHISM . 1S2 



X. 

 INFLUENCES AND EFFECTS ..... . . 209 



XI. 

 HABITATS 233 



XII. 

 CULTIVATION 253 



XIII. 

 GEOGRAPHICAL DISTRIBUTION 266 



XIV. 

 COLLECTION AND PRESERVATION ... .287 



