28 



Mi '1 1'IIOLOGY 



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 bryophytes 



approach this method of antheridium formation 



Fig. 276. — Section of gamctophytc of Lycopodium com- 

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



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

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

 ated tissues. — After Bruchmann. 



in the fact that the 

 inner cell following 

 the periclinal division 

 gives rise to the sper- 

 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), 

 a condition of the 

 archegonium very 

 commonly seen. Be- 

 ginning with the 



