128 



MORPHOLOGY 



antheridium development resembles closely the eusporangiate method 

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

 interesting to note that only the Anthocerotales among bryoph'ytes 

 approach this method of antheridium formation in the fact that the 



inner cell following 

 the periclinal division 

 gives rise to the sper- 

 ~r matogenous tissue. 

 The sperms are re- 

 markable among 

 pteridophytes in be- 

 ing biciliate, a char- 

 acter which belongs 

 to the sperms of 

 bryophytes (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), 



FlG. 276. Section of gametophyte of Lycopodium com- a condition of the 



planatum, showing crown (g) bearing antheridia (a) and archegonium 

 archegonia (a') (in one, e, the embryo sporophyte has de- irm i v c Ppn 



veloped), and the tuberous region (c) with highly different!- commom y ***' 



ated tissues. After BRUCHMANN. gi nnm g 



Very 



with the 



