SPERMATOPHYTA— ANGIOSPERMS— HELOBIAE 333 



Fig. 131. Pond-weed {Potamogeton natans). 1. 

 Apex of flowering shoot. 2. Flower viewed from 

 above. 3. Flower viewed from side. 4. Diagram 

 of flower. (After Wossidlo). 



Fi?. 132. Pond weed (Po/amoseion). Common in fresh water 

 ponds. 



