686 



A TEXTBOOK OF THEORETICAL BOTANY 



'%^*\^ 



Micropyle 



Nucellar beak 



Archegonia 

 Nucellus 



i j- Megaspore wall 

 ]}l * Prothallus 



Fig. 686. — Pinus sylvestris. 

 Longitudinal section of 

 an ovule with archegonia 

 at fertilization stage. 



Integument 



Nucellus 



Female 

 prothallus 



Archegonium 



••.•.«'*?«** 



Fig. 687. — Pinus sylvestris. Enlarged view of the apical 

 region of the ovule showing two archegonia. 



