Fig. 2. — Potamogeton lucens. 



Fig. I. — Potamogeton natans. 



Fig. 3. — Potamogeton heterophyllus. 



Fig. 4. — Potamogeton lonchites. 



PLATE XXXIV.- WIDE-RANGING SPECIES OF PONDWEEDS. (From Morong.) 

 (After Biological Survey.) 



