THE FERN 103 



(b) Archegonia. The archegonia, or female sex organs, 

 are small, finger-like projections in the region of the 

 sinus, or notch, of the prothallium. Compare care- 

 fully their shape and structure with that of the an- 

 theridia. When the archegonia are mature each 

 one contains a single egg cell. 



Make drawings showing the location of the sex 



organs on the prothallium, and also showing the 



character of these organs as seen with higher power. 



3. Development. After fertilization, which takes place 



within the archegonium, the fertilized egg cell undergoes a 



cleavage and gradually develops into a young fern. It soon 



develops its own roots and leaves and becomes a perfectly 



independent plant. The plant produced in this way is the 



sporophyte generation. 



