XVI 



CONTENTS 



D. Green sporogonia . 

 £. Liverworts as pioneers . 

 Section 74. Mosses . . ■ • 



A. Reproduction 



B. Increase of the sporophyte 



•PAGE 



403 

 404 

 404 

 405 

 407 



CHAPTER TEN: THE VASCULAR PLANTS 



Section 75. Introductory . 413 



Pteridophytes : 



Section 76. Ferns . . ... . . 415 



Section 77. Horsetails 422 



Section 78. Club mosses . ... 424 



Selaginella 425 



Spermatophytes : 



Section 79. Gymnosperms ......... 431 



A. Two kinds of cones 432 



B. Pollination ... .... 432 



C. The pollen tube 434 



D. The embryo ... .... 434 



E. The seed 435 



F. Why two sets of names ? . . . 436 



G. Pollen grains not exactly microspores . . . 437 

 If. The female gametophyte .... 437 



/. Generations in the seed .... 437 



J. Summary of the life history of a gymnosperm . 438 



JC. General summary . .... 439 



Section 80. Angiosperms ......... 440 



A. The greatest group of plants 441 



B. The flower 441 



C. The male gametophyte 443 



D. The female gametophyte 443 



E. Double fertilization ...... 444 



A Plant breeding . 446 



Key to Index and Guide in Review 450 



Index . 454 



