II. Monocotyledons] LXX'VIII. NAIADES. 



239 



956. Zannichellia palustris, L. 



Hor7ied Po7idweed. 



957. Ruppia marilima, L. 



SeaR. 



958, Potamogeton natans, L. 959. Potamogeton heterophyllus, Schr. 

 Broad Pondweed. P. gramineus, L. 



Vart07is-leaved Pondweed. 



