CHAPTER VII 



THE FERNS (PTEEIDOPHYTA} 



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THE Pteridophytes or Ferns, using the latter term in 

 its widest sense, include those plants sometimes known 

 as the Vascular Cryptogams, which while evidently re- 

 lated to the mosses differ from them in the very much 

 more highly developed sporophyte, which here becomes 

 an independent plant. Indeed, it is the sporophyte or 

 non-sexual generation of the ferns which is the plant 

 as it is ordinarily understood, the gametophyte being 

 usually small and inconspicuous and of short duration. 



It will be remembered that in considering the Bryo- 

 phytes great differences were noted in the relative 

 development of gametophyte and sporophyte; that 

 while in Riccia, for example, the sporophyte is nothing 

 more than a capsule filled with spores, in Anthoceros 

 the spore-formation is subordinated to a considerable 

 extent, and there is developed a well-marked assimila- 

 tive issue, consisting of green cells with large intercellu- 

 lar spaces, and stomata communicating with the outside 

 as in the vascular plants. Moreover, this sporophyte is 

 not limited in its growth, but continues to elongate as 

 long as the gametophyte remains alive. Owing to the 

 absence of a root, however, the sporophyte still remains 

 dependent upon the gametophyte for water, and to 

 some extent for food also; but the well-developed 



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