SECTION XIV 

 Ferns 



i. THE LIFE-HISTORY OF FERNS 



The life-cycle of flowering plants, which may be shortly stated as seed, 

 plant, flower, and seed again, is simple enough to be popularly understood; 

 but that of the Ferns is so much more con) plica ted, and evidenced on such 

 a microscopic scale, as to be mainly unknown even to those who grow Ferns 

 or appreciate their beauty. In the first place, the Fern is differentiated 

 from the flowering plant by bearing neither obvious 

 flowers nor obvious seeds, although, as we shall presently 

 see, microscopic equivalents of these are really produced 

 in the course of the events which precede the appearance 

 of a second generation -of young Ferns. Instead of a 



A 



Fig. 303. Sporangium 

 of Cystopteris 



a, Annulus; b, broader 

 cells of same where 

 bursting takes place 

 (magnified). 



Fig. 304.-Section of Leaf and Sorus of Nephrodium Filix-mas 

 s, Sporangia ; i, indusium (magnified). 



seed proper, which is always the result of fertilization brought about by the 

 conjunction of reproductive cells existing in the pollen grain as the male, 

 and in the embryo seed as the female, the Fern produces on its fronds an 

 enormous number of asexual spores, microscopically minute bodies which 

 consist only of & reproductive cell protected by a husk or shell. These 

 spores are contained in tiny capsules or pods (sporangia) (fig. 303), and their 

 minuteness may be conceived when it is stated that even these pods are only 

 definable as such under a good lens, though they contain, as a rule, several 

 scores of spores apiece. These capsules in their turn are collected into 

 groups (fig. 304), and it is the method of these groupings and arrangements 



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