Fig. 2.- — Potamogeton lucens. 



Fig. I. — Potamogeton natans. 



Fig. 3. — Potamogeton heterophyllus. 



Fig. 4. — Potamogeton lonciiites. 



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



(After Biological Survey.) 



