Potamogeton natans 36 



Potamogeton oakesianus 40 



Potamogeton cr ispus 40 



Potamogeton ampl if ol ius 40 



Potamogeton pulcher 40 



Potamogeton nodosus 40 



Potamogeton alpinus 46 



Potamogeton gr amineus 46 



Potamogeton illinoensis 46 



Potamogeton praelongus 52 



Potamoteton r ichardsoni i 52 



Potamogeton per f ol iatus 52 



Selected References 56 



Ruppia 57 



Ruppia mar itima 57 



Selected References 59 



ZANNICHELLIACEAE 59 



Zannichell ia 59 



Zannichellia palustr is 59 



NAJADACEAE 61 



Najas 61 



Key to Species 61 



Najas guadalupensis 61 



Najas f lexilis 61 



Najas gracillima 64 



Najas minor 64 



Selected References 64 



LITERATURE CITED 67 



111 



