TABLE OF CONTENTS. XV11 



PAGE 



pregnation of Thuja orientalis, Juniperus communis, and /. Sabina, 

 424 426 ; evolution of the impregnated germinal-vesicle in Conifer* 

 generally, 426, 427; production and growth of the pro-embryo, 427 

 430; non-ramification of pollen-tubes in Abietineae, 430; several cor- 

 puscula impregnated in Taxus by the expanded end of one pollen-tube, 

 430 ; development of the pro-embryo in Taxus, 430 ; Hartig's obser- 

 vations on this subject, 430, note ; production of the pro-embryo in 

 Juniperus and Thuja, 431, 432 ; development of the embryo of Coni- 

 ferae, 432. Historical review : 432. 



CHAPTER XVI. 



KEVIEW 434 



Comparison of the development of mosses and liverworts with that of 

 ferns, Equisetacese, Rhizocarpeae, and Lycopodiaceae, 434 438; 

 alternation of generations in mosses and ferns, 434, 435 ; homologies 

 of ferns and mosses, 435 ; comparison with liverworts, 435 ; condi- 

 tions of life in mosses, compared with vascular cryptogams, 435, 436 ; 

 occurrence of thickenings of the cell-walls of sporiferous generations 

 of mosses and ferns, 436 ; want of natural foundation for the separa- 

 tion of mosses and liverworts into only two groups, 436, 437 ; their 

 division into four groups, 437 ; formation of the embryo of Coniferae 

 intermediate between that of the Phaenogams and higher Cryptogams, 

 438, 439 ; general considerations, 439 441. 



Note on the cell-multiplication of the apex of the stem of the leafy 



Jungermanniae 442 



Explanation of the figures 443 



Index 493 



