;oo 



C.AMKTOl'HYTE OF FILICALES 



in some species they may endure for years, multiplying exten- 

 sively by gemmae, and so form conspicuous mats upon the moist 

 trunks and rocks. The archegonia and anthericlia are usually 

 borne upon the same gametophyte. Some genera, however, are 

 strictlv dioecious, producing small antheridial or male gameto- 

 phytes and larger archegonial or female gametophytes. Small 

 male gametophytes occur not uncommonly among any of the 

 genera, owing doubtless to their poorer nourishment. The sex- 

 ual organs are developed upon the under side of the gametophyte 

 (Fig. 228, C), probably because this position is of advantage in 

 keeping them in contact with any water that may fall upon the 



Fig. 228. 



Fig. 229. 



Fig. 228. Gametophyte of the Filicales: A, germination of the spore. 



B, early appearance of the thalloid structure of the gametophyte owing to 

 the formation of an apical cell, x. C, mature gametophyte — an, antheridia; 

 <//-, archegonia; r, rhizoids; v, apical cell or growing point. 



Fig. 229. Structure of reproductive organs: ./. antheridium as seen in 

 section, just before the discharge of the gametes. B, male gamete. C. 

 sectional view of archegonium — g, female gamete. 



