XVI 



CONTENTS 



Section 74. 



PAGE 



D. Green sporogonia 403 



E. Liverworts as pioneers . .... 404 

 Mosses . 404 



A. Reproduction 405 



B. Increase of the sporophyte . ... 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 

 H. The female gametophyte . . . 437 



/. Generations in the seed ..... 437 



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



K. 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 



F. Plant breeding 446 



Key to Index and Guide in Review 450 



Index 454 



