22 



Figure 9. 

 Ceratophyllum demersum: A. habit * '/->. B. leaves * 1 *&. 

 C. leaf segment showing broad-based marginal tooth 

 *4Vfe. D. fruit »3. 



Ceratophyllum echinatum: E. leaf * lVfe. F. spinulose 

 leaf segment * 4'/^. G. fruit * 3. 



