128 



MORPHOLOGY 



antheridium development resembles closely the eusporangiate method 

 of Sporangium development, and is always associated with it. It is 

 interestin g to note that only the Anthoccrotales amon^ brvoph vtes 

 approach this method of antheridium formation in the fact that the 



i nner cell followi ng 

 th e periclinal divisi on 

 p |ives rise to the sp er- 

 mato genous tiss ue. 

 T he sperms are r e- 

 m a r kable amo n g 

 pteridophvtes in be - 

 ing biciliate, a char- 

 a cter which belori gs 

 to the sperms of 

 b ryophytes (fig. 282). 

 Archegonium. — 

 The archegonium 

 also resembles that of 

 the Anthocerotales in 

 being an embedded 

 structure. The out- 

 line of its develop- 

 ment is as follows: 

 It begins as a super- 

 ficial cell, which 

 divides by a trans- 

 verse wall (fig. 283), 

 the outer cell being 

 the primary neck cell, 

 the inner one the 

 inner cell. The inner 

 cell divides by a 

 transverse wall, re- 

 sulting in a row of 

 three cells (fig. 284), 

 a condition of the 

 archegonium very 

 commonly seen. Be- 

 ginning with the 



Fig. 276. — Section of gamctophyte of Lycopodium oom- 

 planatum, showing crown (f) bearing antheridia (a) and 

 archegonia (a') (in one, e, the embryo sporophyte has de- 

 veloped), and the tuberous region (c) with highly differenti- 

 ated tissues. — After Beuchmann. 



