188 



PLANT MORPHOLOGY 



vertical wall, or by two vertical walls at right angles to each other, each 

 segment giving rise to an antheridium. Frequently additional antheridia 

 are budded off from the base of the others. 



The archegonium initial is a superficial cell that, like the antheridium 



Fig. 154. Sex organs of Anthoceros, X 500. A, B, C, stages in development of the anther- 

 idium; D, young archegonium showing transverse division of axial cell; E, formation of 

 cover cell, primary neck canal cell, and primary ventral cell; F, division of primary neck 

 canal cell and formation of ventral canal cell and egg; G, later stage with four neck canal 

 cells; H, mature archegonium with egg ready for fertilization. (A to C, Anthoceros pulcher- 

 rimus; D to H, Anthoceros fusiformis.) 



initial, does not become papillate. The usual three vertical walls appear, 

 cutting off the wall cells from the primary axial cell. The latter divides 

 transversely (Fig. 154/)), while a second transverse division occurs in the 

 outer cell, resulting in a row of three cells (Fig. 154£'). These are the 



