To far,,!. 136.J 



Fig. 104.— a, Photomicrograph showing three arehegonia. h. Photomicro- 

 graph showing to the left tlie canal of an archegoniura leading into 

 the arohegonium proper. A pollen-tube is seen just penetrating 

 the upper end of the embryo-sac ; the generative nucleus is to be seeS 

 close to the upper end of the right-hand archegoniura. 



